Bangle stuck with Updating Boot0...

Wed 2021.09.29

I may not be able to resolve your issue @Tx , collecting a bit more detail should assist others.

What process/tutorial was used to update the bootloader? Link please

After resetting using these steps, do we have the same scenario described above?

https://www.espruino.com/Bangle.js#reset­ting-without-loading-any-code

Are you able to step through this process, and if so, at what line is the last possible?

Updating the firmware without a smartphone

https://www.espruino.com/Bangle.js#firmw­are-updates

Another idea to try:

Banglejs not booting
see link   'It's usually pretty much impossible to 'brick' it since the bootloader won't overwrite itself.'