Secure bootloader¶

This section contains information how to build a secure bootloader for NeedForHeat with ESP-IDF. There is anonther page that describes how to build NeedForHeat firmware that uses a secure bootloader. For more general information, you may also want to read the Espressif secure boot documentation.

You only need to follow these steps for an ESP32 that does not have secure boot enabled yet, or had its bootloader overwritten.

Prerequisites¶

ESP-IDF installed.

Build bootloader¶

Use the following command to build the bootloader from the root of the repository:

idf.py bootloader -C bootloader/

Burn secure boot key to eFuse¶

This only needs to be performed once per ESP32. Use the following command to burn the secure boot key to the eFuse and follow the instructions:

espefuse.py burn_key secure_boot_v1 bootloader/build/bootloader/secure-bootloader-key-256.bin

Flash bootloader for the first time¶

Use the following command to flash the bootloader for the first time:

esptool.py --chip esp32 --before=default_reset --after=no_reset write_flash --flash_mode dio --flash_freq 40m --flash_size 4MB 0x1000 bootloader/build/bootloader/bootloader.bin

Flash bootloader after initial flash¶

Use the following command to flash the bootloader after initial flash:

esptool.py --chip esp32 --before=default_reset --after=no_reset write_flash --flash_mode dio --flash_freq 40m --flash_size 4MB 0x0 bootloader/build/bootloader/bootloader-reflash-digest.bin