In the friend’s Android, the device said “DFU file not found” even though it was the latest file from the Espruino website.
This seems very odd - is it possible you'd just clicked the 'Download Espruino' link at the top of https://www.espruino.com/Download without going to 'Find a Binary' and 'Bangle.js 2'?
The ZIP you get from 'Download Espruino' contains firmwares for every device, and NRF Connect won't know which one to use so will give you that error.
Yup, I just double checked and it was the file under “Find a Binary”. I’m double sure because my browser asked if I wanted to download the same file again.
I tried flashing it again just in case, but the same error came up.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
This seems very odd - is it possible you'd just clicked the 'Download Espruino' link at the top of https://www.espruino.com/Download without going to 'Find a Binary' and 'Bangle.js 2'?
The ZIP you get from 'Download Espruino' contains firmwares for every device, and NRF Connect won't know which one to use so will give you that error.