sphinx-key/factory

Sphinx Key Factory App

The main function of this app is to write any update.bin files from the sd card to the flash of the ESP, and configure the ESP so that on the next boot, it boots the freshly written app.

Background Reading

• Partition Tables: https://docs.espressif.com/projects/esp-idf/en/latest/esp32c3/api-guides/partition-tables.html
• Over-the-Air Updates: https://docs.espressif.com/projects/esp-idf/en/latest/esp32c3/api-reference/system/ota.html

Flashing factory and sphinx-key

• First flash the factory app here using the usual espflash command, but add the --partition-table flag and point it to table.csv here. See espflash -h for more info.
• Then use esptool.py to flash the sphinx-key binary at offset 0xc0000.
• Finally use this command to tell the ESP to boot the sphinx-key binary first ( there is no update to write to the ESP yet, so we don't boot the factory app ): otatool.py switch_ota_partition --slot 0