Flash MicroPython on watch

DFU ZYOS is actually DFU 2v05, and LOCKUP means the app you uploaded (MicroPython) locked up without running (or at least kicking the Watchdog timer).

It could be:

• Not kicking the watchdog
  
• Trying to use 32kHz oscillator or the switching power supply circuit (I can't actually remember if Bangle.js has these)
  
• Maybe something else?
  
  

Honestly, for something like this I think you'll need to break the watch open and attach to the SWD pins behind the LCD. Once you've done that you could then actually debug the code properly, and if MicroPython is hanging or causing a hardfault you'll be able to see exactly where.

It's a bit of a pain initially, but it'll save you weeks of work when done :)