LN882H TNCE RGBCW WiFi LED bulb - LN882HKI flashing tutorial, UART to USB, pinout

p.kaczmarek2 3051 31

TL;DR

Flashed a TNCE TY-BK-A60 / LN882HKI RGBCW WiFi LED bulb with OpenLN882H to make it cloud-free and usable with Home Assistant.
Used a simple USB-to-UART setup on the exposed pads, with P21 as the LN882H boot pin and U0-TX/U0-RX as the programming UART.
Backed up the original firmware first, but the dump was interrupted before the full 2MB image completed.
GPIO Doctor helped identify the PWM pins, and the bulb ended up running full RGBCW control successfully.

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Post #1
21446472 19 Feb 2025 11:40

Here's step by step guide for the LN882 (LN882HKI by Lightning Semi) TY-BK-A60 LED bulb firmware change. This will let you to run the device cloud free and pair with Home Assistant. Device will be flashed with our Tasmota/Esphome inspired firmare, OpenLN882H. A simple USB to UART converted will be used for that. The programming process shown here will be fairly simple and will not require full bulb disassembly. The bulb was bought on Ali for few $, it can be sometimes even bought for as low as 1$. Let's look at the packaging:

TNCE Smart E27 Bulb - TCDPA601WL265
Model: TY-BK-A60
Manufactured: September 10, 2024
There is also a manual inside, but we don't need it as we're going to change the firmware:

and the bulb itself:

Bulb teardown
Top dome can be easily removed with some force. I managed to do it with my bare hands:

Then I had to remove the LED board. I had to pry it with screw driver, it was a bit problematic. I broke the part of the bulb edge:

Finally, as you can see, we're getting access to the WiFi MCU:

It's not a Beken chip this time, but a LN882H:

LIGHTNING LN882HKI, to be precise.
You can also see five transistors nearby, so probably bulb uses raw PWMs. No I2C LED controller there.

It is also possible to glance at the power supply circuit in the back:

It's a step down converter based on BP2525, just like usual. It's a very common solution in these products.
I can also see a KP2120 (KP2120SG?) in the background, so the LED circuit might have a separate supply than a WiFi SoC.
There are also flashing pads on the bottom of the board:

P21 may sounds like a Beken pin. I think it's a left over from previous device version which might have used BK7231.

Firmware change
P21 is actually a LN882H boot pin. The programming UART is in the background, U0-TX and U0-RX. First add some flux and Pb solder to the pads:

Then solder wires:

Follow LN882H flashing tutorial:
https://www.elektroda.com/rtvforum/topic4028087.html
https://www.elektroda.pl/rtvforum/topic4028087.html
Here's my full circuit:

Of course, I've also took a backup of original firmware first. It's not full 2MB because I had to interrupt read early, but it seems that data past 1MB mark is just full of 0xFF:
https://github.com/openshwprojects/FlashDumps/commit/5e7d1bf6dac8c79dc68b34dfd6e781d435bfce42

Initial setup
Just like with Tasmota - disconnect boot pin, do power off/on, connect to LN822H access point:

Configure your WiFi:

Get new device IP from DHCP:

Then you need to figure out the GPIO roles. We don't have yet GPIO extraction for this platform, so I used the GPIO Doctor tool from the Web App.

Once you guess the pins with Doctor, you can set them to PWMs in Configure Module menu:

At first I got CW working:
This is how CW controls look like:

CW seems to work good:

Later I found RGB pins, so RGBCW is fully working now.

RGBCW configuration:
Code: JSON
Log in, to see the code

Summary
Flashing process was easy and didn't require full disassembly of the bulb. I have managed to reach the pads with my soldering iron and I didn't have to remove the thread. I also guessed the meaning of pad markings - U0 is used for flashing and P21 is infact the LN882 boot pin. I also managed to guess the GPIO roles with GPIO Doctor, so full RGBCW is working now.
Device can be now paired with Home Assistant, just like in our tutorial.
Let us know if you have also encountered any LN882H devices already. We can help you with flashing and HA setup.
PS: Special thanks to @divadiow for helping me to get this bulb. I've ordered another already, this time E14 thread, we will see if it will be also LN-based...

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#2 21447286 19 Feb 2025 20:48

John Yossarian John Yossarian

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Post #2
21447286 19 Feb 2025 20:48

And would it go via OTA, Tuya-convert + tasmot?
#3 21447295 19 Feb 2025 20:54

p.kaczmarek2 p.kaczmarek2

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Post #3
21447295 19 Feb 2025 20:54

Unfortunately no. It only goes on devices with ESP and, in addition, most new devices are protected.

The LN882HKI is a completely different MCU. We specifically wrote HAL for it to port firmware to it. OpenLN882H (OpenBK port) is in the style of Tasmota and supports some of the Tasmota commands, but it is a completely different code, although the idea is the same.

You'll either have to work with cables as shown in the topic, or alternatively, you can communicate somehow on PW, I sometimes upload batch to devices on request to users.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#4 21447319 19 Feb 2025 21:05

John Yossarian John Yossarian

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Post #4
21447319 19 Feb 2025 21:05

>>21447295 Thanks for the reply. I haven't tried flashing yet, for now I'm gathering info:) I have a couple of these toys, but they are in daily use. Just planning to buy something to play with, with different BK circuits, esp. Well, but this tutorial for LN looks really encouraging:) .
Thanks, pzdr
#5 21447336 19 Feb 2025 21:13

p.kaczmarek2 p.kaczmarek2

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Post #5
21447336 19 Feb 2025 21:13

Well, two comments I have.
First, you're not sure if you're going to get something on LN882H, or BK7231, or BL602, or W800, so don't assume that in advance. But anyway, OpenBK/OpenLN supports most of the now popular platforms from Aliexpress so no problem....
Secondly, you also have flashing tutorials here, also for the BL602: https://www.youtube.com/playlist?list=PLzbXEc2ebpH0CZDbczAXT94BuSGrd_GoM

Just order some product you're interested in, don't set your mind to what SoC will be inside, and then make a topic on the forum and we'll help you step by step to reflash. As if I missed the topic, send me the link to the topic on PW. Only please don't ask me questions on PW - we provide help on the forum.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#6 21447351 19 Feb 2025 21:23

John Yossarian John Yossarian

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Post #6
21447351 19 Feb 2025 21:23

>>21447336 Well, yes, that's true. I don't have the certainty. Once I have something to play with, I'll only wonder. And I will report back on the successes:) .
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#7 21450387 21 Feb 2025 20:56

p.kaczmarek2 p.kaczmarek2

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Post #7
21450387 21 Feb 2025 20:56

I've just ordered more leds myself for testing, we'll see what arrives:
.
I am now awaiting the three packs:
.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
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#8 21456397 25 Feb 2025 23:08

p.kaczmarek2 p.kaczmarek2

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Post #8
21456397 25 Feb 2025 23:08

A package has arrived with this one:
.
It turned out to be based on the BL602 - BW2L module . I am working on it. It is possible to upload OpenBL602.

I have ordered another one:
.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
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#9 21457908 27 Feb 2025 00:37

p.kaczmarek2 p.kaczmarek2

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Post #9
21457908 27 Feb 2025 00:37

It came with:
.
CB2L.
.

Added after 10 [minutes]: .

Ordering another one:
https://www.aliexpress.com/item/1005007254996218.html

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#10 21459470 28 Feb 2025 08:56

bulek01 bulek01

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Post #10
21459470 28 Feb 2025 08:56

I ordered, also, a zigbee version of the bulb.
There is a BZ2L module inside with a BL702 microcontroller.
The bulb is an Ewelink SMART A60

.
.
.

Zigbee2mqtt found it as https://www.zigbee2mqtt.io/devices/CK-BL702-AL-01.html
#11 21459590 28 Feb 2025 10:36

p.kaczmarek2 p.kaczmarek2

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Post #11
21459590 28 Feb 2025 10:36

Zigbee it will run right away, no need to flash, but as if you want to experiment it is also possible to dump and upload the memory:
How to read and back up the flash memory of a BL602/BL702/etc device using BLDevCube? .

In the meantime I have completed the eWeLink E14 with BW2L and BL602, it is flashable but I had to desolder the module because the programming pads are on the bottom of the BW2L.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#12 21461233 01 Mar 2025 12:46

p.kaczmarek2 p.kaczmarek2

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Post #12
21461233 01 Mar 2025 12:46

I flashed this (18W version):
.
Unfortunately the CB2L programming pad is on the bottom. I had to solder it out. Problematic copy.

I ordered one today:
.
15W eWeLink WiFi COOLO.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#13 21463754 03 Mar 2025 10:14

p.kaczmarek2 p.kaczmarek2

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Post #13
21463754 03 Mar 2025 10:14

The E14 led mentioned earlier in this topic from eWeLink turned out to use BL602. Today I also ordered an E14, but not from eWeLink, but from Tuya, to see if it would also be a BL602 or perhaps further BK7231.
.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#14 21468442 06 Mar 2025 12:09

p.kaczmarek2 p.kaczmarek2

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Post #14
21468442 06 Mar 2025 12:09

p.kaczmarek2 wrote:
.
Ordering another:
https://www.aliexpress.com/item/1005007254996218.html
.
Received - 2025.03.06 There is an LN882H with BP5758 inside (not PWM!). KA0600152-ibbd

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#15 21468963 06 Mar 2025 19:45

divadiow divadiow

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Post #15
21468963 06 Mar 2025 19:45

p.kaczmarek2 wrote:
The E14 led mentioned earlier in this topic from eWeLink turned out to use BL602

Assuming eWeLink-C3009-EW-E14-BWL2-bulb-20250225.bin is from this bulb:

Code: Text
Log in, to see the code

In eWeLink app:
FW Name: CK-BL602-5PWM-01

Offers update to 1.5.0

which is downloaded from http://52.57.99.135:8088/ota/rom/UOqtau8qtAt8...1024.new.2.bin?deviceid=xxxxxxxxxxxxxxxxxxxxx
(deviceID removed)

After update the boot log is more verbose. Recently built.

Code: Text
Log in, to see the code

Attachments:

user1.1024.new.2.bin (539.81 KB) You must be logged in to download this attachment.
#16 21469247 06 Mar 2025 21:53

p.kaczmarek2 p.kaczmarek2

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Post #16
21469247 06 Mar 2025 21:53

@divadiow the Matter bulb also arrived:

ESP8684-WROOM-05, I didn't research it yet. I hope it's not flash-protected?

Added after 44 [seconds]:

Found this: ESP8684 is the new nomenclature for ESP32-C3 based modules

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#17 21469251 06 Mar 2025 21:54

divadiow divadiow

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Post #17
21469251 06 Mar 2025 21:54

ooh. I hope it isn't too, but I have a small pile of ESP Matter devices that are
#18 21469307 06 Mar 2025 22:20

p.kaczmarek2 p.kaczmarek2

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Post #18
21469307 06 Mar 2025 22:20

Do you know the debug log output baud rate for this module?

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#19 21469308 06 Mar 2025 22:21

divadiow divadiow

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Post #19
21469308 06 Mar 2025 22:21

74880?

#20 21469327 06 Mar 2025 22:29

p.kaczmarek2 p.kaczmarek2

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Post #20

21469327 06 Mar 2025 22:29

Normal mode:


ESP-ROM:esp8684-api2-20220127
Build:Jan 27 2022
rst:0x1 (POWERON),boot:0xc (SPI_FAST_FLASH_BOOT)
SPIWP:0xee
mode:DIO, clock div:1
Valid secure boot key blocks: 0
ECDSA ESP-ROM:esp8684-api2-20220127
Build:Jan 27 2022
rst:0xf (BROWNOUT_RST),boot:0xc (SPI_FAST_FLASH_BOOT)
SPIWP:0xee
mode:DIO, clock div:1
Valid secure boot key blocks: 0
ECDSA secure boot verification succeeded
load:0x3fcd5d78,len:0x203c
load:0x403acb70,len:0x6bc
load:0x403aeb70,len:0x485c
load:0x403ba000,len:0x2068
entry 0x403acb70
W (178) boot: custom bootloader with compress ota!
ECDSA zero_code_product: enter main: 523 ms

zero_code_product: Current Free Memory: 122100, Minimum Ever Free Size: 122088, Largest Free Block: 112640
zero_code_core: Signature verification successful
E (1125) factory_reset: Reboot count: 1, reset reason: 15
light_matter: restore done: 868 ms

E (1227) wifi:failed to post WiFi event=2 ret=259
E (4036) wifi:failed to post WiFi event=1 ret=259
E (4131) wifi:failed to post WiFi event=3 ret=259
zero_code_core: Current Free Memory: 86080, Minimum Ever Free Size: 58644, Largest Free Block: 59392
controller lib commit: [77e7dbb]
controller rom commit: [3314f9d]
chan:1,max_power:80
chan:2,max_power:80
chan:3,max_power:80
chan:4,max_power:80
chan:5,max_power:80
chan:6,max_power:80
chan:7,max_power:80
chan:8,max_power:80
chan:9,max_power:80
chan:10,max_power:80
chan:11,max_power:80
chan:12,max_power:80
chan:13,max_power:80
chan:14,max_power:80
E (4773) chip[ZCL]: Duplicate attribute override registration failed
matter_one_core: Current Free Memory: 13108, Minimum Ever Free Size: 13108, Largest Free Block: 9984
matter_one_core: Current Free Memory: 13108, Minimum Ever Free Size: 13108, Largest Free Block: 9984
matter_one_core: Current Free Memory: 13108, Minimum Ever Free Size: 13084, Largest Free Block: 9984
matter_one_core: Current Free Memory: 13108, Minimum Ever Free Size: 13084, Largest Free Block: 9984
matter_one_core: Current Free Memory: 13108, Minimum Ever Free Size: 13084, Largest Free Block: 9984
matter_one_core: Current Free Memory: 13096, Minimum Ever Free Size: 11576, Largest Free Block: 9984
chan:1,max_power:80
chan:2,max_power:80
chan:3,max_power:80
chan:4,max_power:80
chan:5,max_power:80
chan:6,max_power:80
chan:7,max_power:80
chan:8,max_power:80
chan:9,max_power:80
chan:10,max_power:80
chan:11,max_power:80
chan:12,max_power:80
chan:13,max_power:80
chan:14,max_power:80
matter_one_core: Current Free Memory: 13096, Minimum Ever Free Size: 11576, Largest Free Block: 9984
matter_one_core: Current Free Memory: 13056, Minimum Ever Free Size: 11576, Largest Free Block: 9984
matter_one_core: Current Free Memory: 13056, Minimum Ever Free Size: 11576, Largest Free Block: 9984
matter_one_core: Current Free Memory: 13056, Minimum Ever Free Size: 11576, Largest Free Block: 9984
zero_code_core: Current Free Memory: 23864, Minimum Ever Free Size: 10668, Largest Free Block: 13056
zero_code_product: Current Free Memory: 23864, Minimum Ever Free Size: 10668, Largest Free Block: 13056
factory_reset: Current Free Memory: 27412, Minimum Ever Free Size: 10668, Largest Free Block: 13056
factory_reset: Current Free Memory: 27412, Minimum Ever Free Size: 10668, Largest Free Block: 13056

Boot mode:

 
ESP-ROM:esp8684-api2-20220127                    
Build:Jan 27 2022                                                
rst:0x3 (RTC_SW_SYS_RST),boot:0x4 (DOWNLOAD(UART0))            
Saved PC:0x40054770                                      
Download boot modes disabled

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.

#21 21469338 06 Mar 2025 22:36

divadiow divadiow

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Post #21
21469338 06 Mar 2025 22:36

oh dear
#22 21469421 07 Mar 2025 00:17

p.kaczmarek2 p.kaczmarek2

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Post #22
21469421 07 Mar 2025 00:17

Well, it seems I don't have much options. Buying a replacement module would cost too much, maybe at most I could try to botch there WB2S that I received from a reader... but it's not pin to pin compatible...

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#23 21469470 07 Mar 2025 06:54

divadiow divadiow

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Post #23
21469470 07 Mar 2025 06:54

yeh, ESP Matter devices aren't often much fun it seems
#24 21469723 07 Mar 2025 10:38

p.kaczmarek2 p.kaczmarek2

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Post #24
21469723 07 Mar 2025 10:38

Is there a way to tell whether Matter device is using ESP or BK from the outside? Before buying...

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#25 21469802 07 Mar 2025 11:35

divadiow divadiow

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Post #25
21469802 07 Mar 2025 11:35

hmm. I thought I had a kind of pattern to it. Moes can sometimes be ESP. The CozyLife /Aiyatto stuff has been a good bet so far

https://www.elektroda.com/rtvforum/topic4081005.html
https://www.elektroda.com/rtvforum/topic4075524.html
https://www.elektroda.com/rtvforum/topic4077326.html

I had a feeling that the homekit stuff were less likely to be ESP, but I don't know what I'm basing that on. As for labelling... I don't think so.
#26 21473843 10 Mar 2025 15:06

p.kaczmarek2 p.kaczmarek2

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Post #26
21473843 10 Mar 2025 15:06

Two bulbs arrived today.
- Smart Life/Tuya Smart TY-E14-220VB*AT 5W

https://pl.aliexpress.com/item/1005007654887555.html

LN882H

- COOLO eWeLink - EW-A60-15W

https://www.aliexpress.com/item/1005006412570573.html
It's BW2L as well

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.

#27 21877012 03 Apr 2026 21:31

Baustromverteiler Baustromverteiler

Level 6

Posts: 6

Rate: 2

Post #27

21877012 03 Apr 2026 21:31

So I recently got the the same bulb, but I cant enter download mode ... the GPIOA_9 pin is connected to the SP21 pad (checked with a multimeter) but when I try to boot into download mode the serial terminal just stays dark, the device only comes back to life if I remove the connection of SP21 to GND. Here is the bootlog, any chance they changed something in the firmware or am I just too dumb?


bootloader build time: 13:48:19
config item not found perip_param value
-- tuya project compile time: Jul 24 2023 10:07:45--
ble mac[98:7a:d7:2d:17:f8]
[BLIB_I]BLIB Ver: 1.0.3 [build time:Jan 19 2023 12:14:45][0x010003ff]
xTaskCreate, name: rw_task, priority: 9, stack size: 2048
xTaskCreate, name: worker, priority: 2, stack size: 1536
xTaskCreate, name: ty_main, priority: 3, stack size: 4096
xTaskCreate, name: IDLE, priority: 0, stack size: 1024
xTaskCreate, name: Tmr Svc, priority: 10, stack size: 2048
Before enter tuya_main, Total:164284; Free:151944
GPIOA_9 high level, will enter Normal mode!
Failed to enter ate mode! Start tuya user main.
xTaskCreate, name: tuya_app_main, priority: 4, stack size: 4096
xTaskCreate, name: TUYA_TCPIP, priority: 9, stack size: 2048
tkl_ethernetif_init
tkl_ethernetif_init
[01-01 00:00:00 ty I][lr:0x100c8f17] mqc app init ...
xTaskCreate, name: wq_system, priority: 3, stack size: 5120
[01-01 00:00:00 ty I][tal_thread.c:184] thread_create name:wq_system,stackDepth:5120,totalstackDepth:7168,priority:3
xTaskCreate, name: wq_highpri, priority: 4, stack size: 4096
[01-01 00:00:00 ty I][tal_thread.c:184] thread_create name:wq_highpri,stackDepth:4096,totalstackDepth:11264,priority:4
xTaskCreate, name: sys_timer, priority: 5, stack [01-01 00:00:00 ty D][tal_thread.c:203] Thread:wq_highpri Exec Start. S
et to Runningsize: 4096
 Stat
[01-01 00:00:00 ty D][tal_thread.c:203] Thread:sys_timer Exec Start. Set to Running Stat
[01-01 00:00:00 ty I][tal_thread.c:184] thread_create name:sys_timer,stackDepth:4096,totalstackDepth:15360,priority:5
[01-01 00:00:00 ty E][lr:0x100d3da5] uf_open 8 err 8
[01-01 00:00:00 ty E][soc_flash.c:77] uf file 8 can't open and read
[01-01 00:00:00 ty E][light_memory.c:102] power mem read err
[01-01 00:00:00 ty N][lr:0x100750c7] reset is 0>>
xTaskCreate, name: thread_shade, priority: 5, stack size: 2048
[01-01 00:00:00 ty N][lr:0x10088c87] ble serv not closed, forbid open!
[01-01 00:00:00 ty N][lr:0x10074a49] BleSwitch=1
[01-01 00:00:00 ty E][lr:0x100d3da5] uf_open 8 err 8
[01-01 00:00:00 ty E][soc_flash.c:77] uf file 8 can't open and read
[01-01 00:00:00 ty E][light_memory.c:102] power mem read err
[01-01 00:00:00 ty N][lr:0x100750c7] reset is 0>>
[01-01 00:00:00 ty N][lr:0x10074a67] first bright up
[01-01 00:00:00 ty N][lr:0x100750c7] reset is 0>>
[01-01 00:00:00 ty N][lr:0x100bff7b] key_addr: 0x1ec000   block_sz 4096
[01-01 00:00:00 ty N][lr:0x100c0255] get key:
0xbf 0xcb 0xc0 0x92 0x8 0x63 0x76 0xdd 0xc9 0xaa 0xd1 0x15 0xe2 0x90 0x90 0xdf 
[01-01 00:00:00 ty N][lr:0x10083e21] uni_random_init...
[01-01 00:00:00 ty N][lr:0x100840c5] tuya_tls_rand_init ok!
----- tkl_watchdog_init
wdg shift_left_num:0x10, set num:65535, top:0x0d
xTaskCreate, name: health_monitor, priority: 5, stack size: 1536
[01-01 00:00:00 ty E][lr:0x100c862b] logseq empty
tkl_cpu_sleep_mode_set 95 1 0
tkl_cpu_sleep_mode_set 95 0 0
tkl_wifi_set_lp_mode 1566, en 0, dtim 0
[01-01 00:00:00 ty E][tal_wifi.c:714] tal_wifi_lp_dis: set wifi lp mode fail(-26880)
[01-01 00:00:00 ty N][lr:0x100ab26b] mf is open need stop fastconnect
set work mode 1, is open 0, current ln mode: 0
wifi not start, turn on first
adapt wifi start <m:1>, hw_ready:0
start rf preprocess and image cal
[WLIB_E]idx=00, iq_hex_cal=0x807A, i=128, q=122, iavg= 71, qavg= 25
[WLIB_E]idx=01, iq_hex_cal=0x8076, i=128, q=118, iavg= 49, qavg=  6
[WLIB_E]idx=02, iq_hex_cal=0x8070, i=128, q=112, iavg= 59, qavg= 16
[WLIB_E]idx=03, iq_hex_cal=0x7E68, i=126, q=104, iavg= 18, qavg= 44
[WLIB_E]idx=04, iq_hex_cal=0x795E, i=121, q= 94, iavg= 33, qavg= 44
[WLIB_E]idx=05, iq_hex_cal=0x807A, i=128, q=122, iavg= 61, qavg= 19
[WLIB_E]idx=06, iq_hex_cal=0x8077, i=128, q=119, iavg= 21, qavg= 12
[WLIB_E]idx=07, iq_hex_cal=0x8071, i=128, q=113, iavg= 20, qavg=  3
[WLIB_E]idx=08, iq_hex_cal=0x7F68, i=127, q=104, iavg= 49, qavg= 12
[WLIB_E]idx=09, iq_hex_cal=0x7A5E, i=122, q= 94, iavg=  9, qavg=  0
[WLIB_E]idx=10, iq_hex_cal=0x807A, i=128, q=122, iavg= 58, qavg= 15
[WLIB_E]idx=11, iq_hex_cal=0x8077, i=128, q=119, iavg= 26, qavg= 11
[WLIB_E]idx=12, iq_hex_cal=0x8070, i=128, q=112, iavg= 14, qavg=  7
[WLIB_E]idx=13, iq_hex_cal=0x7F68, i=127, q=104, iavg= 67, qavg=  9
[WLIB_E]idx=14, iq_hex_cal=0x7A5E, i=122, q= 94, iavg=  8, qavg= 15
[WLIB_E]idx=15, iq_hex_cal=0x807A, i=128, q=122, iavg= 56, qavg= 18
[WLIB_E]idx=16, iq_hex_cal=0x8077, i=128, q=119, iavg= 17, qavg=  2
[WLIB_E]idx=17, iq_hex_cal=0x8070, i=128, q=112, iavg=  9, qavg=  7
[WLIB_E]idx=18, iq_hex_cal=0x7F68, i=127, q=104, iavg= 74, qavg= 29
[WLIB_E]idx=19, iq_hex_cal=0x7A5E, i=122, q= 94, iavg=  6, qavg= 39
[WLIB_E]idx=20, iq_hex_cal=0x7F7B, i=127, q=123, iavg= 45, qavg= 42
[WLIB_E]idx=21, iq_hex_cal=0x7F78, i=127, q=120, iavg= 21, qavg= 30
[WLIB_E]idx=22, iq_hex_cal=0x7E73, i=126, q=115, iavg= 44, qavg= 40
[WLIB_E]idx=23, iq_hex_cal=0x7B6D, i=123, q=109, iavg= 58, qavg= 20
[WLIB_E]idx=24, iq_hex_cal=0x7564, i=117, q=100, iavg= 66, qavg=  6
xTaskCreate, name: wifi_cfg, priority: 5, stack size: 2048
xTaskCreate, name: mac_task, priority: 9, stack size: 2048
[WLIB_I]cap_comp = 10, xtal_capbank_tab:[0]:50 [1]:45 [2]:45 [3]:45 [4]:60 [5]:80 [6]:80 [7]:80 
[WLIB_I][original]phy_tab_1f:0x56, phy_tab_20:0x3C
[WLIB_I][efuse]phy_tab_1f:0x56, phy_tab_20:0x3C
[WLIB_I][flash]phy_tab_1f:0x56, phy_tab_20:0x3C, tx_pwr_comp_all=0, tx_pwr_comp_b=0, tx_pwr_comp_gn=0
[WLIB_I]==>temp_sect:2,phy_tab_1f:0x56,phy_tab_20:0x3C
[WLIB_I]<==temp_sect:2,phy_tab_1f:0x56,phy_tab_20:0x3C
XTAL CAP VAL:10.
wifi stop
wifi sta start
[WLIB_I]LN882H WiFi Lib Ver: 1.1.3 [build time:Apr 24 2023 15:10:58][0x010103ff]
[WLIB_I]STA_Startup.
STA startup!
[WLIB_I]Disconnected.
[WLIB_I]HwInd:UKI:0
[WLIB_I]Disconnected.
current work mode 0
No need to switch mode, mode:0
xTaskCreate, name: mf_test, priority: 4, stack size: 5120
adapt wifi start <m:2>, hw_ready:1
[01-01 00:00:01 ty N][lr:0x1006bbe5] mf_init succ
[01-01 00:00:01 ty N][lr:0x10075da9] < TuyaOS V:3.5.4 BS:40.00_PT:2.3_LAN:3.5_CAD:1.0.5_CD:1.0.0 >
< BUILD AT:2023_01_09_16_12_01 BY ci_manage FOR tuyaos-iot AT ln882h >
IOT DEFS < WIFI_GW:1 DEBUG:1 KV_FILE:0 LITTLE_END:1 SL:0 OPERATING_SYSTEM:98 RELIABLE_TRANSFER:0 >
 
[01-01 00:00:01 ty N][lr:0x10075db3] xxxxxxxxxxxxxx_LN882H:1.0.0
[01-01 00:00:01 ty N][lr:0x10075e7b] connect mode is 5
[01-01 00:00:01 ty E][lr:0x100d3da5] uf_open 2 err 8
[01-01 00:00:01 ty E][soc_flash.c:77] uf file 2 can't opetkl_thread_release, name: mf_test
n and read
[01-01 00:00:01 ty E][user_flash.c:211] Prod data read err
[01-01 00:00:01 ty E][lr:0x100d3da5] uf_open 2 err 8
[01-01 00:00:01 ty E][soc_flash.c:77] uf file 2 can't open and read
[01-01 00:00:01 ty E][user_flash.c:211] Prod data read err
[01-01 00:00:01 ty N][lr:0x1006bc09] prodtest find ssid: tuya_mdev_test1
set work mode 1, is open 1, current ln mode: 0
current work mode 0
No need to switch mode, mode:0
adapt wifi start <m:2>, hw_ready:1
adapt wifi start <m:2>, hw_ready:1
[01-01 00:00:01 ty N][lr:0x100a76cb] wifi soc init. pid:key4xxxxxxxxxxx firmwarekey:key4xxxxxxxxxxxxxxx ver:1.0.0
[01-01 00:00:01 ty N][lr:0x100aae0d] start wifi link params validate, nc_tp:1 md:0
[01-01 00:00:01 ty N][lr:0x100aae95] gw_wsm.nc_tp:1
[01-01 00:00:01 ty N][lr:0x100aae9f] gw_wsm.md:0
[01-01 00:00:01 ty N][lr:0x10098f61] Last reset reason: 0
[01-01 00:00:01 ty N][lr:0x10098ff1] gw_cntl->gw_wsm.stat:1
[01-01 00:00:01 ty N][lr:0x1009908b] gw_cntl->gw_if.abi:0 input:0
[01-01 00:00:01 ty N][lr:0x10099099] gw_cntl->gw_if.product_key:keyxxxxxxxxx, input:key4xxxxxxxxxx
[01-01 00:00:01 ty N][lr:0x100990a5] gw_cntl->gw_if.tp:0, input:0
[01-01 00:00:01 ty N][lr:0x100990b9] gw_cntl->gw_if.firmware_key:key4xxxxxxxxx, input:key4xxxxxxxxxxx
[01-01 00:00:01 ty N][lr:0x100996bd] enter success_proc
[tkl_wifi_get_mac:1229] if: 0, mac: f8:17:2d:d7:7a:97
ble_mac: 98:7a:d7:2d:17:f8
[01-01 00:00:01 ty N][lr:0x100996d1] serial_no:xxxxxxxxxxxx
[01-01 00:00:01 ty N][lr:0x10075fe7] frame init ok
[01-01 00:00:01 ty N][lr:0x1006f44b] opMeshRemoterCtrlInit!
xTaskCreate, name: remoter_cmd_deal, priority: 3, stack size: 2560
set work mode 3, is open 1, current ln mode: 0
current work mode 0
[WLIB_I]Disc[01-01 00:00:01 ty I][tal_thread.c:184] thread_create name:remoteornnected.
_cmd_deal,stackDepth:2560,totalstackDepth:28672,priority:3
[01-01 00:00:02 ty N[WLIB_I]LN882H WiFi Lib Ver: 1.1.3 [build time:Apr 24 202][lr:0x10076055] ble remote ok
3 15:10:58][0x010103ff]
[WLIB_I]SoftAP_Startup.
SoftAP startup!
[WLIB_I]HwInd:UKI:0
[WLIB_I]Channel scanning not needed
[WLIB_I]User Preferred channel idx 5-0
[WLIB_I]Selecting 20MHz ch from One of ... 0 1 2 3 4 5 
[WLIB_I]Selected Channel Tbl Idx 5-0
[WLIB_I]AP: Starting network in 5-0
[WLIB_I]Connected.
[WLIB_I]Status: Start Successful. Entering Enable State. 
tkl_thread_release, name: tuya_app_
[WLIB_I]Disconnected.
[WLIB_I]Channel scanning not needed
[WLIB_I]User Preferred channel idx 5-0
[WLIB_I]Selecting 20MHz ch from One of ... 0 1 2 3 4 5 
[WLIB_I]Selected Channel Tbl Idx 5-0
[WLIB_I]AP: Starting network in 5-0
[WLIB_I]Connected.
[WLIB_I]Status: Start Successful. Entering Enable State. 
[tkl_wifi_get_mac:1229] if: 0, mac: f8:17:2d:d7:7a:97
ble_mac: 98:7a:d7:2d:17:f8
[tkl_wifi_get_mac:1229] if: 1, mac: f8:17:2d:d7:7a:96
ble_mac: 98:7a:d7:2d:17:f8
ssid:SmartLife-7A97; pwd:; channel:6, ecn:0, max conn:1, hidden:0beacon:100, mac:f8:17:2d:d7:7a:96; start:1
[WLIB_I]Disconnected.
ip info: 
        ip:      192.168.176.1
        gw:      192.168.176.1
        netmask: 255.255.255.0
server config:
        ip:       192.168.176.1
        ip start: 192.168.176.2
        ip end:   192.168.176.2
port:67
lease:2880
renew:2880
max client:1
[WLIB_I]LN882H WiFi Lib Ver: 1.1.3 [build time:Apr 24 2023 15:10:58][0x010103ff]
[WLIB_I]SoftAP_Startup.
SoftAP startup!
ap_startup_cb 137, wifi softap up
------- dhcp stop ----------
-------DUMP DHCP SERVER_CONFIG----------
server_config.server=192.168.176.1
server_config.port=67
server_config.lease=2880
server_config.renew=2880
server_config.ip_start=192.168.176.2
server_config.ip_end=192.168.176.2
server_config.max=1
-----------------END--------------
IP_POOL: i=0 192.168.176.2
xTaskCreate, name: dhcpd, priority: 4, stack size: 1280
dhcpd_task start...
[WLIB_I]HwInd:UKI:0
[WLIB_I]Channel scanning not needed
[WLIB_I]User Preferred channel idx 5-0
[WLIB_I]Selecting 20MHz ch from One of ... 0 1 2 3 4 5 
[WLIB_I]Selected Channel Tbl Idx 5-0
[WLIB_I]AP: Starting network in 5-0
[WLIB_I]Connected.
[WLIB_I]Status: Start Successful. Entering Enable State. 
[WLIB_I]Disconnected.
[WLIB_I]Channel scanning not needed
[WLIB_I]User Preferred channel idx 5-0
[WLIB_I]Selecting 20MHz ch from One of ... 0 1 2 3 4 5 
[WLIB_I]Selected Channel Tbl Idx 5-0
[WLIB_I]AP: Starting network in 5-0
[WLIB_I]Connected.
[WLIB_I]Status: Start Successful. Entering Enable State. 
[01-01 00:00:02 ty N][lr:0x100abab3] cur stat:13  0x10075ad5 -->>
[01-01 00:00:02 ty N][lr:0x100abaed] wifi netstat changed to:13  -->>
[01-01 00:00:02 ty N][lr:0x100abb03] report wifi netstat[13] to callback  -->>
[01-01 00:00:02 ty N][lr:0x10075aed] last wifi stat:255, wifi stat 13
[01-01 00:00:02 ty N][lr:0x10075af9] size:111184
[01-01 00:00:02 ty N][lr:0x10075c53] start ez & ap auto blink
[01-01 00:00:02 ty N][lr:0x100add2d] timer stated, short timer:0x0, long timer:0x100adb6d
[01-01 00:00:02 ty N][lr:0x100cc683] bt startup attr:ff
[01-01 00:00:02 ty N][lr:0x10088457] upd product_id type:1 key4xxxxxxxxxxxxxxx
xTaskCreate, name: host_main_thread_hdl, priority: 8, stack size: 5120
[01-01 00:00:02 ty I][tal_thread.c:184] thread_create name:host_main_thread_hdl,stackDepth:5120,totalstackDepth:33792,pr
iority:8
[01-01 00:00:02 ty I][lr:0x100bb165] le acl buf sz = 251,max buf = 5 
 
[01-01 00:00:02 ty I][lr:0x100b9b83] acl buf sz = 251, max pkt = 5, avail pkt = 5
 
[01-01 00:00:02 ty I][lr:0x100bb62d] GAP init: stop adv
[01-01 00:00:02 ty I][lr:0x1007e781] ble_hs_timer reset:100 
[01-01 00:00:02 ty I][lr:0x10080ee5] Stack sync
[01-01 00:00:02 ty I][lr:0x10080ec5] Init/Deinit Event
[01-01 00:00:02 ty N][lr:0x10088419] ty bt sdk init success finish
[01-01 00:00:02 ty N][lr:0x100bbb53] Start Adv
[01-01 00:00:02 ty N][lr:0x100999cf] __devos_init_evt success
[01-01 00:00:02 ty I][lr:0x100bb62d] GAP init: stop adv
[01-01 00:00:02 ty I][lr:0x1007e781] ble_hs_timer reset:0 
[01-01 00:00:02 ty N][lr:0x100bbb53] Start Adv
[01-01 00:00:02 ty N][lr:0x10087fc9] ble adv updated
xTaskCreate, name: TCP_ap_v4, priority: 5, stack size: 3584
[01-01 00:00:02 ty I][tal_thread.c:184] thread_create name:TCP_ap_v4,stackDepth:3584,totalstackDepth:37376,priority:5
[tkl_wifi_get_mac:1229] if: 0, mac: f8:17:2d:d7:7a:97
ble_mac: 98:7a:d7:2d:17:f8
[tkl_wifi_get_mac:1229] if: 1, mac: f8:17:2d:d7:7a:96
ble_mac: 98:7a:d7:2d:17:f8
[01-01 00:00:02 ty E][lr:0x100a93c9] timer is not run,wait
[01-01 00:00:02 ty I][lr:0x1007e885] ble_hs_timer_exp:
reboot type(0:power-on;1:soft-rst;2:wdt-rst): 0
reboot count: 0
[ln_ty_sdk_ver: 0.0.5_alpha or 0x00000500] [build time:2022-05-17_14:57:03]
[Git info: develop_198ece8]
[BLIB Ver: 1.0.3 or 0x010003ff] [build time:Jan 19 2023 12:14:45]

edit: so I fooled around a bit with the timing of connecting sp21 to ground and got this:

GPIOA_9 low level, will enter ATE mode!

so the chip seems to recognize that the pin is low ... but I still cant flash or read from the device in this state ... isnt ATE mode some kind of test mode and not the desired download mode`?

#28 21877420 04 Apr 2026 14:57

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

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Post #28
21877420 04 Apr 2026 14:57

I didn't pay attention to this log. Can anyone check? @divadiow ?
I would still suggest testing different baud rates, in both our flasher and original LN882H tool. How do you connect this, did you try swapping RX and TX, how do you power the module?

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#29 21877425 04 Apr 2026 15:02

insmod insmod

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Post #29
21877425 04 Apr 2026 15:02

It shouldn't be printing anything if in boot mode.

A9 must be low before powering it up.
If there's no log - boot mode. To double check - open COM port in any terminal program at 115200 baud and write "version".
It should respond with "Mar 14 2021/00:23:32"
#30 21877429 04 Apr 2026 15:12

divadiow divadiow

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Post #30
21877429 04 Apr 2026 15:12

power off/unplug USB port and 3.3v to device in between flash attempts. A9 grounded before powering-on
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Topic summary

✨ The discussion revolves around flashing the LN882H TNCE RGBCW WiFi LED bulb (LN882HKI by Lightning Semi) with custom firmware, OpenLN882H, to enable cloud-free operation and integration with Home Assistant. Users share insights on the flashing process, which requires a USB to UART converter and does not necessitate disassembling the bulb. The conversation also touches on the challenges of OTA flashing due to MCU differences, with users discussing various models and their compatibility with different firmware. Several users report on their experiences with other LED bulbs, including those based on BL602 and BL702 microcontrollers, and share links to additional flashing tutorials and resources.
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LN882H TNCE RGBCW WiFi LED bulb - LN882HKI flashing tutorial, UART to USB, pinout

FAQ

TL;DR: For owners of the TNCE TY-BK-A60 bulb, the LN882HKI can be flashed over 3.3 V UART using U0-RX, U0-TX, GND, and the P21 boot pad; as one expert put it, "A9 must be low before powering it up." This solves cloud lock-in and enables OpenLN882H with full RGBCW control and Home Assistant pairing on this LN882H-based E27 bulb. [#21877425]

Why it matters: This thread turns a cheap Tuya WiFi bulb into a documented, repeatable cloud-free smart-lighting target instead of a one-off hardware hack.

Option	Chip / path	Flash method	Result from thread
TNCE TY-BK-A60	LN882HKI / LN882H	UART on U0 + P21 boot pad	Full RGBCW working in OpenLN882H
Some older ESP devices	ESP family	OTA / Tuya-convert	Not applicable here
Similar AliExpress bulbs	BL602 / CB2L / BW2L / BZ2L / LN882H	Varies by module and pad access	Must identify module first
Matter bulb example	ESP8684-WROOM-05	UART download blocked	Flash path effectively blocked

Key insight: On LN882H bulbs, success depends less on the app brand and more on the exact chip, UART port, and boot pin behavior. In this case, using U0 instead of U1 was the decisive fix when flashing initially failed.

Quick Facts

The documented bulb is a TNCE Smart E27 Bulb TCDPA601WL265, model TY-BK-A60, manufactured on September 10, 2024. [#21446472]
The original dump was read only partially, but the author reports the flash is not full 2 MB in useful data and appears to be 0xFF past the 1 MB mark. [#21446472]
The working OpenLN882H RGBCW mapping uses 5 PWM channels on LN882H pins 1, 4, 5, 6, and 7. [#21446472]
The bulb was bought on AliExpress for a few US dollars and was stated to sometimes cost as low as $1, making it a low-risk test target. [#21446472]
Similar bulbs in the same buying stream arrived with BL602, CB2L, BW2L, BZ2L, LN882H, and ESP8684 platforms, so the external listing does not guarantee the internal SoC. [#21473843]

How do you flash a TNCE TY-BK-A60 RGBCW WiFi bulb with an LN882HKI chip using a USB-to-UART adapter and the U0/P21 pads?

You flash it over the LN882H boot UART, not by OTA. 1. Open the E27 bulb enough to access the board, then solder wires to U0-TX, U0-RX, GND, and P21. 2. Pull P21 low, power the module from a 3.3 V USB-to-UART adapter, and start the LN882H flasher. 3. Remove the boot strap, power-cycle, join the OpenLN882H access point, then configure Wi-Fi and pins. The thread shows this worked without fully removing the screw thread and ended with full RGBCW support. [#21446472]

What is the P21 or SP21 pad on an LN882H bulb board, and how is it used to enter boot mode?

P21, also labeled SP21 on some boards, is the LN882H boot-selection pad tied to GPIOA_9. You use it by grounding it before power-up so the chip enters boot mode instead of normal firmware startup. Later troubleshooting confirmed that the pad continuity to GPIOA_9 was correct and that the module recognized the low state. If the pad is released, the bulb resumes normal operation and prints standard boot logs again. [#21877012]

Why doesn’t Tuya-convert or OTA flashing work on LN882HKI bulbs the way it does on some ESP-based devices?

Tuya-convert does not work here because the LN882HKI is not an ESP chip and the thread states the OTA path applies only to some ESP devices. The author says most newer devices are also protected, so even that route is shrinking. OpenLN882H follows a Tasmota-like idea, but it is separate firmware with its own HAL for LN882H. On this bulb, the practical method is wired flashing over UART, not cloud or OTA replacement. [#21447295]

Which UART pads should be used on the LN882H bulb for flashing, and how do U0 and U1 differ during troubleshooting?

Use U0, not U1, for flashing the LN882H bulb. The original guide identifies U0-TX and U0-RX as the programming UART, while a later user initially wired the U1 interface because it showed serial logs. That caused confusion: U1 exposed runtime output, but flashing only worked after moving the wires back to U0. This is the key troubleshooting difference: logs alone do not prove you are on the bootloader UART. [#21878105]

Why would an LN882H bulb print normal boot logs or enter ATE mode instead of download mode when GPIOA_9 is pulled low?

It does that when the timing, wiring, or UART choice is wrong. The thread shows one device printed “GPIOA_9 high level, will enter Normal mode!” when the boot strap was ineffective, and later printed “GPIOA_9 low level, will enter ATE mode!” when the low level was detected. In this case the real fault was using U1 instead of U0, so the user saw behavior that looked wrong even though the boot pin state changed. Power must be fully removed between attempts. [#21878105]

What baud rates and serial commands should be tested when an LN882H flasher shows no response in boot mode?

Start with 115200 baud in a terminal and send the command version. The thread’s recovery advice says that a module already in boot mode should answer with “Mar 14 2021/00:23:32”. Another expert also suggested testing different baud rates in both the custom flasher and the original LN882H tool if there is still no response. If you see no boot text at all, that can be normal for boot mode. [#21877425]

How do you verify that an LN882H module is really in boot mode after grounding A9/P21 before power-up?

Verify it by grounding A9/P21 before power-up, then checking that the module stops printing normal firmware logs. One expert states, “It shouldn’t be printing anything if in boot mode.” To confirm, open the COM port at 115200 baud and type version. A valid bootloader response is “Mar 14 2021/00:23:32”. If you still see Tuya startup logs, the chip is in normal mode or you are on the wrong UART. [#21877425]

What is GPIO Doctor in the OpenLN882H web app, and how does it help find RGB and CW pin assignments on an unknown bulb?

“GPIO Doctor” is a diagnostic web-app tool that probes unknown GPIO behavior, helps identify which pins drive LEDs or functions, and speeds board bring-up when no pin extraction exists for that platform. In this bulb, the author used it because LN882H did not yet have automatic GPIO extraction. That let them first identify the CW channel, then later find the RGB pins and finish a working RGBCW setup in the Configure Module menu. [#21446472]

How do you configure full RGBCW output in OpenLN882H for the Tuya TNCE Smart E27 bulb model TY-BK-A60 after flashing?

Set the discovered LED pins as five PWM outputs in OpenLN882H. The working JSON in the thread assigns pin 1 = PWM;4, 4 = PWM;5, 5 = PWM;1, 6 = PWM;2, and 7 = PWM;3 for the TY-BK-A60 on LN882H. The author first got CW working, then found the RGB channels and confirmed full RGBCW operation. After that, the bulb could be paired with Home Assistant like other OpenBK-style devices. [#21446472]

What’s the difference between an LN882H bulb that uses raw PWM channels and one that uses a BP5758 LED driver?

A raw-PWM bulb drives its LED channels directly from multiple transistor-switched PWM outputs, while a BP5758 bulb uses a dedicated LED driver IC. The first TY-BK-A60 teardown showed five nearby transistors and no I2C controller, so the author concluded it used raw PWMs. A later bulb received on 2025-03-06 still had an LN882H, but this time with BP5758 inside, explicitly noted as “not PWM!” That changes pin discovery and firmware setup strategy. [#21468442]

Which chips have been found inside similar AliExpress smart bulbs besides LN882H, such as BK7231, BL602, BL702, W800, CB2L, BW2L, and BZ2L?

The thread found a broad mix of platforms, not a single family. Reported examples include BL602 on BW2L, BL702 on BZ2L in a Zigbee bulb, CB2L, and additional LN882H units. The author also warns buyers not to assume they will get LN882H, BK7231, BL602, or W800 in advance, because identical-looking AliExpress bulbs vary internally. The practical rule is simple: identify the module after purchase, then choose the flashing method. [#21447336]

What is ATE mode on the LN882H, and how is it different from the actual UART download mode needed for flashing?

“ATE mode” is a factory test mode that confirms a boot pin state, runs manufacturing checks, and is not the same as the serial download bootloader used for firmware flashing. The evidence is direct: one user got “GPIOA_9 low level, will enter ATE mode!” yet still could not flash or read the device. Another expert then clarified that true boot mode should produce no normal log output and should answer the version command on the serial port. [#21877012]

How does OpenLN882H compare with Tasmota and ESPHome for cloud-free bulbs and Home Assistant integration?

OpenLN882H serves the same goal as Tasmota-style firmware: local control, no vendor cloud, and Home Assistant pairing. The author explicitly describes it as Tasmota/ESPHome-inspired and says it supports some Tasmota commands, but it is different code built around a dedicated HAL for LN882H. On this bulb, it exposed a setup AP, accepted Wi-Fi credentials, and then drove full RGBCW output after GPIO mapping. That makes it a practical cloud-free path for non-ESP Tuya bulbs. [#21447295]

What are the safest ways to open and reassemble an E27 smart bulb for flashing without fully disassembling the thread or damaging the LED board?

Open the top diffuser first, then disturb as little else as possible. The author removed the dome by hand, then carefully pried the LED board, noting that this step was the risky one and broke part of the edge. The important takeaway is that full disassembly was unnecessary: the flashing pads were reachable without removing the E27 thread. Use controlled force, support the board evenly, and plan wiring before levering the LED plate. [#21446472]

How can you tell from the outside whether a Matter smart bulb is more likely to use an ESP8684/ESP32-C3 module or a Beken-based module before buying?

You usually cannot tell reliably from the outside. One participant asked exactly that, and the reply was that there was no dependable labeling pattern, only weak brand-level guesses. The thread mentions some Moes devices can be ESP, and CozyLife / Aiyatto products had looked promising, but this was not presented as a rule. A Matter bulb in the same discussion arrived with ESP8684-WROOM-05, and its UART download mode was blocked, showing why external branding is a poor predictor. [#21469802]

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