Hot-swap TZ offset with browser locale in firmware binary

[thebentern]

Flow in bash:
sed -i 's/tzplaceholder /CST6CDT,M3.2.0,M11.1.0\x0/' firmware.bin
truncate --size=-32 firmware.bin
sha256sum firmware.bin | xxd -r -ps >> firmware.bin

[thebentern]

https://github.com/nayarsystems/posix_tz_db/blob/master/zones.csv

[jp-bennett]

We will need to ask esptool to generate a byte of checksum, and replace the 33rd byte from the end of the file. Then the last 32 bytes can be trimmed and replaced with the sha256sum.

[jp-bennett]

Rak4631 doesn't need any hashing or checksum modifications. Just overwrite the placeholder bytes with the right string and null-terminate it. RP 2040 still to be checked.