My proposal would be to put the configuration variables (e.g. interval, encryption keys, etc) in EEPROM. We have 2x3 KiB of EEPROM, that should be plenty.
See diff for my proposed memory layout. If you agree, I can implement this.
The EEPROM can be read simply by reading the corresponding raw memory addresses. To write the EEPROM, we can use a custom binary based on probe-rs, which reads a TOML file with the config and writes to the target's EEPROM. Alternatively, instead of writing to the target directly, we could generate a binary file or hexfile and flash that to the target using cargo-embed.
dbrgn
commented
3 years ago 
My proposal would be to put the configuration variables (e.g. interval, encryption keys, etc) in EEPROM. We have 2x3 KiB of EEPROM, that should be plenty.
See diff for my proposed memory layout. If you agree, I can implement this.
The EEPROM can be read simply by reading the corresponding raw memory addresses. To write the EEPROM, we can use a custom binary based on
probe-rs, which reads a TOML file with the config and writes to the target's EEPROM. Alternatively, instead of writing to the target directly, we could generate a binary file or hexfile and flash that to the target usingcargo-embed.(Support for flashing EEPROM is WIP.)