Magic bytes
Homie for ESP8266 firmwares contain magic bytes allowing you to check if a firmware is actually an Homie for ESP8266 firmware, and if so, to get the name, the version and the brand of the firmware.
You might be wondering why Homie_setFirmware() instead of Homie.setFirmware(), this is because we use special macros to embed the magic bytes.
Values are encoded as such within the firmware binary:
| Type | Left boundary | Value | Right boundary |
|---|---|---|---|
| Homie magic bytes | None | 0x25 0x48 0x4F 0x4D 0x49 0x45 0x5F 0x45 0x53 0x50 0x38 0x32 0x36 0x36 0x5F 0x46 0x57 0x25 |
None |
| Firmware name | 0xBF 0x84 0xE4 0x13 0x54 |
actual firmware name | 0x93 0x44 0x6B 0xA7 0x75 |
| Firmware version | 0x6A 0x3F 0x3E 0x0E 0xE1 |
actual firmware version | 0xB0 0x30 0x48 0xD4 0x1A |
Firmware brand (only present if Homie_setBrand() called, Homie otherwise) |
0xFB 0x2A 0xF5 0x68 0xC0 |
actual firmware brand | 0x6E 0x2F 0x0F 0xEB 0x2D |
See the following script for a concrete use case:
firmware_parser.py