Posted at 2020-02-11 by @gfwilliams

Please can you try re-downloading the firmware from http://www.espruino.com/binaries/travis/master/ ? And ensure it is the espruino_2v04_banglejs.zip one

I just tried here and it works fine for me.

The BANK0 invalid message means that the firmware update failed and left Bangle.js with no firmware - but it's fine, the bootloader is still there - you just need to write the correct firmware and it'll start working again.

Is it possible your phone is going to sleep in the middle of doing the firmware update, or something like that? If you have access, maybe try a different phone in case that helps.

Posted at 2020-02-12 by @fanoush

Other options

• try turning bluetooth off/on or restarting phone
• in nrfConnect in Settings-> DFU options try to lower number of packets to e.g. 5
• try nRF Toolbox instead of nrfConnect

Also if nothing helps try to post output or screenshot of nrfConnect log, it is in the menu 'show log' after device is connected.

Posted at 2020-02-13 by pc3b3r

@gfwilliams, yes I went away from the watch with the mobile during the upload.
Ok, found the issue: I downloaded the firmware twice and of course the name of the zip file has been changed espruino_2v04_banglejs (1).zip.
Guess which is the right one?

Using nRF Toolbox was easy to understand because it's not validating it by showing Status: Invalid file

Posted at 2020-02-13 by @gfwilliams

Great! And...

yes I went away from the watch with the mobile during the upload.

Yes, that'd do it!

Posted at 2020-03-10 by labarks

I had the same issue since I tried using the espruino_2v04.399_banglejs.zip firmware which was in http://www.espruino.com/binaries/travis/­master/.
But using espruino_2v04_banglejs.zip firmware from http://www.espruino.com/binaries/travis/cad1b987f8c6a3af1fcc6984980f4023c4732aca/ worked.