This was forked from RP2040 Serial Bootloader to provide the similar functionality but instead read and load .uf2 file from SD card.
Blink example was copied from https://github.com/usedbytes/pico-blink-noboot2
uf2tool.py was copied from https://github.com/rhulme/pico-flashloader - licensing included in file (same, BSD-3-Clause license).
This example depends on the SD card library https://github.com/Tails86/no-OS-FatFS-SD-SPI-RPi-Pico which was forked from https://github.com/carlk3/no-OS-FatFS-SD-SPI-RPi-Pico
After .uf2 files are created, either bootloader.uf2 or bootloader_blink_noboot2_combined.uf2 may be loaded on the RP2040. Then either blink_noboot2_w_header.uf2 or bootloader_blink_noboot2_combined.uf2 may be copied onto an SD card as application.uf2 when flash through the bootloader is desired. For the case of the combined uf2 on SD card, the bootloader code will be ignored. This allows for only a single file to be kept track of.
This is a bootloader for the RP2040 which enables code upload via UART.
There's a more complete description at: https://blog.usedbytes.com/2021/12/pico-serial-bootloader/
There are currently two tools I know of which can be used to upload code to it:
- serial-flash - my tool written in
go - pico-py-serial-flash - a similar tool written in Python, contributed by another user.