Building custom firmware

Posted on Tue 21st, July 2020

• #1

Tamás

Just wondering if the bootloader accepts any custom firmware built with the Nordic tools? Does it have to be signed to be able to flash it onto the Bangle.js?
• #2

fanoush

Any made for Nordic SDK12 and SoftDevice S132 3.0. Package must be signed as Nordic secure DFU requires it, but any key will do since the signature check is disabled.
• #3

Gordon

So yes, you can flash whatever you want.

If you want to use Espruino signing key then that's actually public in the Espruino GitHub repo.

Obviously it's a bit of a security issue so we've disabled buttonless DFU - you have to be physically with the Bangle to press the correct buttons to reboot it into bootloader mode first.

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