Bangle.js 2 destroyed firmware

Hi - as others have said, you didn't actually break your Bangle.js firmware, you just overwrote a bit of JS. From http://www.espruino.com/Bangle.js+Development :

Note: If you've used Espruino before, make sure the Upload button (middle of the screen) shows RAM underneath it. Otherwise by writing to Flash you can remove the watch's built-in menu (you can just re-add it by removing and installing bootloader using https://banglejs.com/apps)

So now you've uploaded the firmware, your watch is actually booting to the Bangle.js logo?

So I think your connection issue is maybe just your computer getting confused after rebooting Bangle.js and doing firmware updates and things. Try disabling and re-enabling bluetooth on your computer (maybe even a reboot) and see if that helps?

As others have said, maybe try other devices too. Once you get the app loader connected and re-upload the Bootloader app it'll all be fixed