[Solved] Flashing of CB3S / BK7231N from DS06 door/windows sensor fails

Hello,

I recently stumbled upon a bunch of Tuya window/door sensors DS06 and became interested in flashing Openbeken onto them. I had a look at this teardown and followed the disassembly steps. I have no previous knowledge of flashing Openbeken, so this paragraph

Quote:

I do not describe the changes of the CB3S batch here, because it was discussed e.g. for CB2S, but I will only emphasize that the lines RX / TX are occupied by TuyaMCU, so if we want to program, we have to cut them off or unsolder that IC ...

confused me, but I still tried flashing the chip without desoldering or cutting any traces.


I used the GUI tools and successfully read the firmware from the chip (after some tries, sometimes got stuck at reading a sector). But whenever I tried to flash the new firmware, it always gets stuck at reading a random sector and then errors out.


After this, I unsoldered the CB3S chip from the board and tried flashing it this way. The process now seemed to go further, even reaching the writing stage, but then it yet again got stuck at some sector writing the firmware and errored out.

I tried multiple different USB-to-TTL adapters and different cables, but if you think that might be the problem, I can continue testing different ones. I still have 2 untouched sensors around, so I can try anything you propose to get a successful flash. Also, if you need any further logs or firmware backups, please let me know. I would really like to try out Openbeken as it looks like a promising software for these new Tuya chips.

Greetings,
Andy

Hello, have you tried lower baud rates?

It should flash outside circuit, I flashed hundreds of Beken already.

Sorry for the late response, I tried experimenting with a lower baud rate. In the end, the problem was solved by using shorter cables for flashing as well as the lower baud rate. Maybe some of my longer cables were faulty.