How to upload arduino bootloader to a custom samd21 usig Jlink mini

Wow a glimmer of hope, cant believe it is already 1 month.

But as i said the project is abandoned. I have switched to using the the RP2040, kind of a bit overkill dual core - 133Mhz . Funny thing is the RP2040 cannot be bought on chip form yet, so i have to get the components from the raspberry pi pico (since my board is small than the pico), i dont mind though as its dirt cheap, 2$.

The board will arrive tomorrow, and cross fingers it wont be the same nightmare to integrate XD

Hi @John41234

I've seen the RP2040 available as a separate IC here: https://thepihut.com/products/raspberry-pi-rp2040-microcontroller.