After unsuccessful bootloader update - Unable to boot

Hi - How exactly did you update via Bluetooth? Did you just update the apps via https://banglejs.com/apps/ ?

The Bangle effectively has 4 bits of software:

• The DFU bootloader (the thing that says DFV ZYOS - it's actually DFV 2V05)
  
• The Bangle.js/Espruino firmware
  
• The JS Bootloader
  
• The JS Apps
  
  

If you used https://banglejs.com/apps/ you should only really have been able to update the last 2 (and not the first 2). A Firmware Update app does exist on https://banglejs.com/apps/ but this is for Bangle.js 2 and shouldn't work on Bangle.js 1.

Please can you just follow the steps here:
https://www.espruino.com/Bangle.js#resetting-without-loading-any-code

And if that works you can just connect with the app loader again, update the apps (maybe uninstall and reinstall the bootloader if there was some issue there) and you should be fine.

Otherwise did you use the NRF Connect app to to an update? like https://www.espruino.com/Bangle.js#firmware-updates ?

If that failed you'll still be fine, but you just have to follow those steps to update the firmware again.