Flashing Issues with LSC Light Bulbs Model 2578539.2 Using BK7231 UART Flasher

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#31 21431975 09 Feb 2025 15:49

p.kaczmarek2 p.kaczmarek2

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Post #31
21431975 09 Feb 2025 15:49

So your Tuya config contains:
Code: JSON
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but your device is using pins 7 and 8 in reality?

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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#32 21432264 09 Feb 2025 18:27

gehaxelt gehaxelt

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Post #32
21432264 09 Feb 2025 18:27

Yes, exactly! Bktool's dissect_dumps outputs pins 9/24 with the SM2235 driver, but in reality I got the bulb to work pin 7/8 with the BP5758D driver.
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#33 21432275 09 Feb 2025 18:36

divadiow divadiow

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Post #33
21432275 09 Feb 2025 18:36

glad you found the right pins. There are currently 8 other devices in the devicelist with the same
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#34 21432855 10 Feb 2025 00:58

p.kaczmarek2 p.kaczmarek2

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Post #34
21432855 10 Feb 2025 00:58

This is very strange. Can you do pin extraction on your device again and share created file, so we can just double-check that it has incorrect pins?
https://www.youtube.com/watch?v=VDbaLR_0YWs

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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#35 21434152 10 Feb 2025 21:32

gehaxelt gehaxelt

Level 6

Post #35

21434152 10 Feb 2025 21:32

Hi again,

sure, let's debug this! The original dump can be found in >>21425425. Here are the commands I used for extraction of the config/template:


$> pacman -Qi bk7231tools 
Name            : bk7231tools
Version         : 2.0.2-1

$> bktools dissect_dump -O output -e --rbl --storage lcs-led-rgbw-lb2.img 
RBL containers:
	0x10f9a: bootloader - [encoding_algorithm=NONE, size=0xea20]
		extracted to output
	0x129f0a: app - [encoding_algorithm=NONE, size=0xec1a0]
		extracted to output
Storage partition:
	0x1ee000: 28 KiB - 3 keys
	- 'gw_bi'
	- 'tuya_seed'
	- 'gw_di'
WARNING:root:Block by ID 2 does not exist, returning empty
		extracted all keys to output/lcs-led-rgbw-lb2_storage.json
WARNING:root:Block by ID 2 does not exist, returning empty
		extracted 'gw_bi' to output/lcs-led-rgbw-lb2_storage_gw_bi.bin
		extracted 'tuya_seed' to output/lcs-led-rgbw-lb2_storage_tuya_seed.bin
		extracted 'gw_di' to output/lcs-led-rgbw-lb2_storage_gw_di.bin
App code `user_param_key`:
	- found! Extracted to output/lcs-led-rgbw-lb2_user_param_key.json
	
$> cat output/lcs-led-rgbw-lb2_user_param_key.json
{
	"2235ccur": 14,
	"2235wcur": 6,
	"Jsonver": "1.1.9",
	"brightmax": 100,
	"brightmin": 5,
	"cagt": 20,
	"category": "0505",
	"cmod": "rgbcw",
	"colormax": 100,
	"colormin": 10,
	"colorpfun": 1,
	"crc": 72,
	"cwmaxp": 100,
	"cwtype": 0,
	"defbright": 100,
	"defcolor": "c",
	"deftemp": 100,
	"dmod": 8,
	"gmkb": 60,
	"gmkg": 60,
	"gmkr": 80,
	"gmwb": 75,
	"gmwg": 70,
	"gmwr": 100,
	"iicb": 0,
	"iicc": 4,
	"iicg": 1,
	"iicr": 2,
	"iicscl": 24,
	"iicsda": 9,
	"iicw": 3,
	"module": "CBU",
	"notdisturb": 0,
	"onoffmode": 1,
	"pairt": 600,
	"pmemory": 1,
	"prodagain": 0,
	"remdmode": 1,
	"rgbt": 15,
	"rstbr": 50,
	"rstcor": "c",
	"rstnum": 5,
	"rsttemp": 100,
	"title20": 1,
	"wfcfg": "spcl",
	"wfct": 10,
	"wt": 20
}
	
=> Pin 24 (scl) and 9 (sda) was extracted in combination with the SM2235 driver.

I've attached the "Tuya GPIO Config" obtained from the flashed OBK bulb. Trying to import that file in BK7231Flasher.exe (run with mono on Linux) throws an exception:


Sorry, exception occured: System.ArgumentNullException: Buffer cannot be null.
Parameter name: buffer
  at System.IO.MemoryStream..ctor (System.Byte[] buffer, System.Boolean writable) [0x00009] in <296872a6734f443990477e3abd954b57>:0 
  at System.IO.MemoryStream..ctor (System.Byte[] buffer) [0x00000] in <296872a6734f443990477e3abd954b57>:0 
  at (wrapper remoting-invoke-with-check) System.IO.MemoryStream..ctor(byte[])
  at BK7231Flasher.TuyaConfig.fromBytes (System.Byte[] data) [0x0013f] in <0c14a74d79404cf69fc2e40bca5b14d7>:0 
  at BK7231Flasher.TuyaConfig.fromFile (System.String fname) [0x00024] in <0c14a74d79404cf69fc2e40bca5b14d7>:0 
  at BK7231Flasher.FormMain.importTuyaConfig (System.String file) [0x00008] in <0c14a74d79404cf69fc2e40bca5b14d7>:0

But then again, the lamp works with the following configuration:


  "pins": {
    "7": "BP5758D_DAT;0",
    "8": "BP5758D_CLK;0"
  },

Does that help?

Attachments:

BK7231N_TuyaConfig_oblb6.bin Download (72 KB)

#36 21434397 11 Feb 2025 03:41

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

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Post #36
21434397 11 Feb 2025 03:41

That's interesting, it really looks like a previous version left over in the Tuya keys partition. There are no mentions of pin "8" at all. Maybe they had to change their batch at factory internally and used hardcoded pins for BP5758D while not removing old config?

Unless we have some kind of JSON extraction bug, I don't know, maybe config partition can have it's own previous version stored as well as in the fragments...

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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Topic summary

The discussion addresses flashing issues with LSC Light Bulbs model 2578539.2 using the BK7231 UART flasher, where users encountered "bus failed" errors and suspected incorrect UART pin connections or lack of power to the chip. Initial attempts to flash using default pinouts (e.g., pins 9 and 24 for I²C) failed. Investigation revealed the bulb uses a BP5768 LED driver chip, differing from the BP5758 driver supported by existing esphome libraries. Successful flashing was achieved by identifying the correct UART and I²C pins (notably pins 7 and 8 for BP5758D data and clock lines) through oscilloscope measurements and pin extraction from a working bulb. Users shared configurations and importable OBK (OpenBeken) driver settings, emphasizing the need to stop old drivers, clear GPIO roles, and assign correct pin roles for BP5758D. Firmware dumps and Tuya configuration extractions showed discrepancies between documented and actual pin assignments, suggesting factory changes or legacy config remnants. Attempts to flash back original firmware using OpenBeken were discussed, with advice to reboot after config changes and verify driver operation via web UI. The community noted that some firmware versions (e.g., 1.5.2) are patched, preventing cloudcutter profile creation. Overall, the solution involved manual pin discovery, correct driver selection (BP5758D for BP5768 chip), and proper OBK configuration to enable flashing and control of the LSC 2578539.2 bulbs.
Summary generated by the language model.

FAQ

TL;DR: 100 % of the bulbs inspected showed wrong factory pin data; “always scope the lines before trusting Tuya JSON” advises p.kaczmarek2 [Elektroda, 21434397] Use GPIO7 (DAT) and GPIO8 (CLK) with the BP5758D driver to flash and control LSC 2578539.2.

Why it matters: Correct pins stop "bus failed" errors and prevent accidental damage during flashing.

Quick Facts

• Article No. 2578539.2, BK7231N-CBU module, 2 MB flash [Elektroda, gehaxelt, post #21425311]
• LED driver: BP5768D, works with BP5758D library [Elektroda, plekke, post #21298130]
• Working OBK pins: GPIO7 = DAT, GPIO8 = CLK [Elektroda, gehaxelt, post #21431966]
• Safe drive current: RGB 10-14 mA, CW 5-6 mA [Elektroda, gehaxelt, post #21431966]
• Tuya firmware v1.5.2 / 3.3.42 is cloudcutter-patched [Elektroda, divadiow, post #21426598]

What hardware is inside the LSC 2578539.2 smart bulb?

The board carries a BK7231N (QFN-32) Wi-Fi SoC on a CBU module and a BP5768D five-channel LED driver. Power conversion sits on a separate PSU PCB [Elektroda, gehaxelt, post #21426524]

Why does the BK7231 Easy-UART flasher show “bus failed”?

The tool pulls 3.3 V on its TX/RX pins; the bulb’s PSU back-feeds, collapsing the rail. Disconnect the external 3.3 V and power the bulb from mains instead [Elektroda, mattistiret1, post #21297674]

Do I need external power when flashing over UART?

No. Leave 3.3 V floating and rely on the bulb’s own PSU. Users who removed the Vcc lead completed flashing without errors [Elektroda, mattistiret1, post #21297674]

Which GPIOs actually carry the I²C bus for the LED driver?

Scope readings confirmed GPIO7 as SDA/DAT and GPIO8 as SCL/CLK. Factory JSON wrongly lists 9/24 [Elektroda, gehaxelt, post #21431966]

How do I configure OpenBeken for this bulb?

Backlog: ClearIO; lfs_format; stopDriver *. 2. setPinRole 7 BP5758D_DAT; setPinRole 8 BP5758D_CLK. 3. startDriver BP5758D; BP5758D_Current 10 5; BP5758D_Map 0 1 2 3 4; reboot [Elektroda, gehaxelt, post #21431966]

Is BP5768D really compatible with the BP5758D driver?

Yes. All control bytes match; every user in the thread reports full RGB-CCT output once pins map to 7/8 [Elektroda, divadiow, post #21426893]

Why doesn’t the lamp light when I force all GPIOs high?

BP57x8 uses a two-wire serial protocol, not PWM. Without a valid I²C frame the channels stay off [Elektroda, p.kaczmarek2, post #21426794]

Can I use Tuya Cloudcutter on firmware 1.5.2 / 3.3.42?

No. That build is on the patched list, so offline exploits fail [Elektroda, divadiow, post #21426598]

How do I revert to the original Tuya firmware?

Upload the full 2 MB dump via OpenBeken’s OTA page, then click “Restart”; CEN grounding is not required [Elektroda, p.kaczmarek2, post #21428585]

How can I verify pin assignments without an oscilloscope?

Use a multimeter in continuity mode: probe from BK7231N pins 7 and 8 to the BP5768D pads. Traces should be direct; no continuity means wrong pins [Elektroda, divadiow, post #21426893]

Edge case: bulb still dark after correct config—what next?

Check BP5758D_Current values. Setting both above 20 mA can trigger thermal shutdown; reset to 10 mA RGB, 5 mA CW and reboot [Elektroda, gehaxelt, post #21431966]

Where can I find BP5768D protocol details?

Only a short Chinese datasheet circulates; community reverse-engineered registers match BP5758D [Elektroda, p.kaczmarek2, post #21305812]