I have a SODAQ SARA R412m board with a SD card reader attached to SPI. Is there a way to flash new firmware from SD card file on reset/restart? I have read about avr_boot (GitHub - zevero/avr_boot: Arduino Bootloader to Flash from SD Card). But does this also work for ATSAMD21J18. If not, any idea if there is a solution for the SODAQ board?

Thx and best regards.

See the SDU solution with an SD card here: Firmwire over the air - #11 by phlegx