FirmwareHash Namespace Reference

Firmware hash: the identity of the image this board is running. More...

Functions
const uint8_t *	get ()
void	print ()

Detailed Description

Firmware hash: the identity of the image this board is running.

esp_partition_get_sha256() returns the SHA-256 that ESP-IDF appended to the app image at build time, after recomputing it once to check the image is intact. It is therefore NOT sha256(firmware.bin): hashing the whole file folds the appended digest into its own input and can never match this value. To compare a board against a build, use firmware/tools/firmware_digest.py, and to turn a digest into a commit use firmware/tools/which_firmware.py. See FIRMWARE_HASH_VERIFICATION.md.

Any change to the image changes this, with or without a new commit. The build is kept free of absolute paths so the same source hashes the same on every machine – see firmware/tools/reproducible_build.py.

SHA-256 is 32 bytes. The full 64-character hex string is printed for unambiguous identification. Note print() emits uppercase hex; the registry stores lowercase, and which_firmware.py accepts either.

Function Documentation

get()

const uint8_t * FirmwareHash::get ( )

inline

Definition at line 31 of file firmware_hash.h.

References ESP_OK, esp_ota_get_running_partition(), and esp_partition_get_sha256().

Referenced by loop(), print(), sendBoardHeartbeat(), SensorHotfire::sendBoardHeartbeat(), sendBoardHeartbeatTo(), and sendHeartbeat().

print()

void FirmwareHash::print ( )

inline

Definition at line 43 of file firmware_hash.h.

References get(), HEX, and Serial.

Referenced by SensorHotfire::setup(), and setup().