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pvvx / ATC_MiThermometer

Custom firmware for the Xiaomi Thermometers and Telink Flasher
https://github.com/pvvx/pvvx.github.io/tree/master/ATC_MiThermometer
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Bricked MJW5D05MMMC after flashing to fw ver 4.5 using Telink flasher #411

Closed pololevu closed 7 months ago

pololevu commented 7 months ago

I just updated a couple of LYWSD03MMC) devices to v4.5 firmware which went well (not my first time). I then tried to update a MJWSD05MMC from v4.4. All seemed to go well but after supposedly successful completion, the device stayed on the flashing '- - -' screen and was unresponsive to button presses. I tried removing the battery but the device seems dead, no display at all. Can you point me at instruction on how to reflash it?

Thanks.

log: 23:27:11: Connecting to: BTH_B92DA2 23:27:15: Hardware Revision String: V2.3 23:27:15: Software Revision String: V4.4 23:27:15: Firmware Revision String: github.com/pvvx 23:27:15: Detected custom Firmware 23:27:15: Hardware Version: MJWSD05MMC V2.3, Software Version: 4.4, Sensor: SHT4x 23:27:15: Custom config HEX string: 55000200005004ae3100095a 23:27:27: Start DFU 23:28:23: Update done after 55.132 seconds 23:28:27: Disconnected. 23:31:26: Reconnect 23:31:26: NetworkError: Bluetooth Device is no longer in range. 23:31:26: Reconnect 1 from 5 23:31:26: NetworkError: Bluetooth Device is no longer in range. 23:31:26: Reconnect 2 from 5 23:31:26: NetworkError: Bluetooth Device is no longer in range. 23:31:26: Reconnect 3 from 5 23:31:26: NetworkError: Bluetooth Device is no longer in range. 23:31:26: Reconnect 4 from 5 23:31:26: NetworkError: Bluetooth Device is no longer in range. 23:31:26: Reconnect 5 from 5 23:31:26: NetworkError: Bluetooth Device is no longer in range. 23:31:26: Something went wrong, too many reconnects 23:31:54: Searching for devices 23:32:37: NotFoundError: User cancelled the requestDevice() chooser.

pvvx commented 7 months ago

They changed something in the Bluetooth Web API in Chrome on Windows... I haven’t figured it out yet. There are constant connection requests from the adapter without an actual connection to the MJWSD05MMC. I used Android and everything goes well.

pvvx commented 7 months ago

I figured it out - it’s not the API that’s to blame, but the USB-BT adapter on the ATS2851 chip. There is a mistake in it. Causes a cyclic connection... I used another Bluetooth adapter, the built-in RZ616, and everything was fine.

I checked other different USB-BT adapters - everything works.

Only ATS2851 does not work. Causes a cyclic connection until you disconnect the adapter. And it drains the MJWSD05MMC battery. If you disconnect this adapter from USB, the thermometer continues to work normally. There are a lot of bugs in the ATS2851 and this is not the first...

pololevu commented 7 months ago

Thanks for the fast response, FWIW I was using Linux with an AX200 WiFi/Bluetooth adapter, I've used it before and generally it works quite well. I had just flashed two smaller devices with it before trying to flash the MJW5D05MMMC.

Now I have a device which has a completely blank screen and unsurprisingly doesn't show up on a bluetooth scan nor respond to button presses. I would like to try to re-flash it over a serial connection if possible, I should be able to solder wires on to it (provided the pads are not super tiny) but I don't know where to connect to or what serial interface (eg signalling level) or flashing software to use.

Any pointers or suggestions welcome.

pololevu commented 7 months ago

Ok, so now I got the back off the device and I can see VDD, GND, SWS, RX and TX pads, not sure what the SWS pad is for but the others seem pretty obvious. I also found How to flash firmware with USB to UART for MJWSD05MMC? #41 which looks promising...

pvvx commented 7 months ago

On the "The USB-COM adapter writes the firmware in explorer. Web version" home page.

Now I have a device which has a completely blank screen and unsurprisingly doesn't show up on a bluetooth scan nor respond to button presses.

I can't reproduce a similar situation. The reason is not clear.

pololevu commented 7 months ago

Thanks again for the response. I think my issue may have been a stupid mistake on my part - as I mentioned I had just re-flashed two LYWSD03MMC devices successfully, then paired the MJW5D05MMMC and just hit the button to flash it without checking the firmware version so I suspect I accidentally flashed it with the wrong software hence bricking it. I don't think there was a problem with the flasher or the bluetooth interface, just pure stupidity on my part. I will try to update the device using a USB-COM adapter and update and/or close this after that.

pvvx commented 7 months ago

Firmware from LYWSD03MMC should work on MJWSD05MMC. That is, BLE will work and nothing more. Look in the Bluetooth lists for the new "ATC_xxxx".

pololevu commented 7 months ago

Awesome! I can see the device and as you say the BLE is working. I can connect to it from my phone using Telink or TelinkOTA but when I select the correct firmware and try to down load it the message says it is trying to send block 7, it pauses then prints the message "Update error: NotSupportedError: GATT Error Unknown" and then disconnects. I am trying to flash the BTH_v45.bin downloaded from the Github link.

pololevu commented 7 months ago

Aha... I found more examples of this error where the fix was to reboot both the thermometer and the phone. I did that and was able to flash BTH_v45.bin straight away without issues and the device is back up and running. Awesome! Thanks for helping out and especially thanks for all the work on this project.