How to flash MHO-C401N from zigbee back to bluetooth firmware through OTA

[changty6]

Hello! I have a MHO-C401N (has a 'link' icon on the screen) that had been wrongly flashed with the non-N firmware, so the display freezes while the sensor works well with zigbee2mqtt. Now I want to flash it with the correct firmware.
As my understanding to this #586 (comment), I should download the firmware file (xxx.zigbee) to my z2m directory (/config/zigbee2mqtt/), create a fitting index.json file, and add the following to the configuration.yaml

ota:
  zigbee_ota_override_index_location: index.json

After I have done these, I restarted z2m. But I didn't see the sensor appear in the OTA tab. Is there anything I did wrong? Thanks!

[pvvx]

https://github.com/pvvx/ATC_MiThermometer/blob/master/zigbee_ota/index_v52.json

[changty6]

I saw this and saved the json file at /config/zigbee2mqtt/. But I didn't see this frozen C401N sensor appear in the OTA tab. I can see another two C401N (which with correct firmware) showing up with available update.

[changty6]

I can see this frozen C401N in the Devices tab, and it shows the red Z logo with MHO-C401-z as device's name. I can interview it successfully, but it doesn't show up in OTA.

[changty6]

https://github.com/pvvx/ATC_MiThermometer/blob/master/zigbee_ota/index_v52.json

Hello,
I flashed the zigbee file in and now it can be recognized in the Telink Flasher, still as C401. So I downloaded the MHO_C401N_v52.bin file but it said "Size firmware is more 131072 bytes!". What should I do? Thanks!

[pvvx]

1. MHO_C401_v52.bin is 83956 bytes in size, MHO_C401N_v52.bin - 83156 bytes
2. To write Zigbee firmware via BLE to TelinkMiFlasher for MHO C401N you will need a file or paste the link in the file menu: https://github.com/pvvx/ZigbeeTLc/raw/refs/heads/master/bin/1141-0208-01283001-ZMHOC401N.zigbee

[changty6]

Thanks. I re-downloaded the file and got the correct size. Have no idea why the first few downloads I got 182KB file.