CB2L homeylux E27 A60 RGBCTWW 10W 806lm OTA flashing not successful

hi,

last week I bought 2 smart lightbulbs homeylux A60 10W 806lm RGB CTWW

after a teardown I discovered there is no ESP module in it, but a beken CB2L BK7231N wifi bluetooth module, see picture



it works with the hoftronic app( qr code on the box of the bulb ) and the standard Tuya app on my phone.
firmware 1.3.1 / MCU 1.3.1 is what I discovered in the Tuya app
on the PCB where the CB2L is soldered on is a BP1633. for the BP1633 I can not find a datasheet. someone has it?

I can place it in bluetooth pairing (fast blinking) and WIFI AP pairing mode( slow blinking

it is vulnerable for the exploit, but I can not flash it over the air as the firmware version is not in the list of cloudcutter firmware list.

I like to flash the CB2L module as I want it to get it off the cloud. I like to flash openbeken firmware in the bulb

I tried already different firmware versions for the BK7231N in cloudcutter, but no result
.
can someone help what to select as firmware in cloud cutter?

where can I place a problem request for the github of cloudcutter that there is no firmware 1.3.1 selection available

regards,

Michael

Hello, I don't know much personally about cloudcutter, but you can try profiles of similar devices.
If they do not work, then you need to do a full 2MB flash read from your device so we can add a new profile for you.
Btw please note - it's not OBK issue, it's just that simply OTA hack might lack profile for your device.
You can do a 2MB flash dump that way:


NOTE: CB2L has UART pads on back, so you will have to desolder it::

but our video covers it well...

Just do a 2MB firmware read for this device and post here 2MB flash here. I will do everything else for you, I can forward the request to Cloudcutter team and get a profile for you.

Hi,
I've the same smart bulb with the CB2L chip.
I've desoldered and tried to flash but couldn't achieve it.

I'm using the esp01 programmer: https://makeradvisor.com/esp8266-esp-01-usb-serial-programmer/
and plugged the cables as in many tutorials:
tx=>rx
rx=>tx
3v3=>3v3
gnd=>gnd

The problem is it's not getting bus
Getting bus failed, will try again - 5/100!
3v3 reboot or CEN>gnd doesn't work

Like the link above I've soldered a button to the programmer to be able to enter the serial programming mode.
When I hold the button, plug, release and try to "Do firmware backup (read) only" I'll only get Getting bus failed
I've enabled logging and it's like this:


When I don't enter the programming mode:


Has anyone an idea why I can't flash the chip. I've already tried 3 different CB2L.
I did also try it with different power supplies and measured 3.3v

Hey @tufandelice , please show your setup, you can also try using Python flasher:
https://github.com/OpenBekenIOT/hid_download_py/
just like on our WB2L_M1 (BK7231N version of WB2L) flashing video:
https://www.youtube.com/watch?v=2e1SUQNMrgY

Have you tried swapping TX and RX? Also let me check if you have correct pins soldered....

Thanks for your quick reaction,

Yes I did swap rx tx no result.
I didn't try Python yet, I'll try that also


Here are 2 examples

I have programmed CB2L in this topic:
https://www.elektroda.pl/rtvforum/topic3918447.html#20183171
(sorry, not yet translated, but scroll to the photos)
There was no issues at all. I have compared my pad connections with yours and yours seem okay ,however you may have TX2 shorted on second photo.

Please check hid_download_py so we can be 100% sure if it's not somehow a flasher fault and then, if it's still not working, we will try to figure something out.

Also try different baud rates.

PS: hid_download_py will show checksum error, but it can be ignored

No success,

hid_download_py couldn't get the bus. it's not reading.

-I've tried the read command
python uartprogram firmware.bin -d /dev/ttyUSB0 -r
-tried several baud rates
-also checked if there were shorts with continuity test
-resoldered everything
-tried it with a new chip

I'm measuring 3.3 volts so there is no lack of power supply over usb.
is it normal that I'm measuring 3 volts with tx & gnd
and even with rx & gnd

I'm out of options, I don't know what I'm doing wrong

Please try another USB to UART converter. Btw the read command for N platform should be:

I've bought the same kind of usb-ttl converter as in the video and tried all the options but couldn't manage to flash the chip.

I've tried the next routes:
-python code with ubuntu
-windows BK writer
-windows BK7231Flasher

soldered all the pins again with CAT6 UTP cable(solid)

chip measurements with volt meter:
tx-gnd = ~3.2v
rx-gnd = between 0.01v - 0.10v (idle)
rx-gnd = ~ 2.3v (running BK flasher => readonly backup)
3.3v-gnd = 3.3v

already tried a new chip.
I also tried to debug it, it fails with ByteArrayCompare:

The hid_download_py (ubuntu tool) always worked for me, at which stage does it fail for you? Does it manage to start reading anything?

hid_download_py has a misleading "wrong checksum" warning but still saves correct flash.

Cannot get bus.
Same as Windows flasher

And how do you connect the same USB to TTL converter as on the video?

And you are doing power on/off cycle by disconnecting batteries?

Well, something must be still wrong, can you try to shorten the wires substantially?

Keeping wires short in order to reduce stray inductances and capacitances is crucial while flashing devices. I had similar issues even with non-IoT MCUs, for example with PIC18F2550. I am not saying that's the problem, but your wires are very long, compared to the ones I am using in my flashing circuits:

Your wires seem... about six times more long than time.

Added after 1 [minutes]:

Btw if that's CB2L, you are using incorrect command for uartprogram, use the one like on video:

but it still should get bus. https://www.youtube.com/watch?v=2e1SUQNMrgY

It works!!!

Thank you very much.
My cables were too long.

Total cable length now is around 14cm

That's good to know, I will add this information to our FAQ. Can you provide us a 2MB flash dump(backup) for analysis?