C31bootbin Verified Today
Symptom: Message appears, then board resets after 2 seconds.
Cause: Watchdog timer was enabled in the bootloader but not fed when jumping to application that was never flashed.
Solution: Disabled watchdog in bootloader config or flashed a dummy application.
A verified boot binary means the generated boot image has been checked for: c31bootbin verified
| Verification Step | Purpose |
|------------------|---------|
| Header correctness | Checks the 4-byte header (0x0B60, 0x0000, etc.) telling the bootloader the data size and destination address. |
| Checksum integrity | Many C31 bootloaders include a 16-bit checksum (sum of words). Verified = recalculated matches embedded value. |
| Endianness & width | C31 expects big-endian words from an 8-bit ROM. Verified = bytes are ordered correctly (e.g., high byte first). |
| Destination addresses | Confirms all blocks load into internal RAM (0x809800–0x809FFF for C31-40). No out-of-range writes. | Symptom: Message appears, then board resets after 2 seconds
If serial is unavailable, blink an LED in a pattern: If serial is unavailable, blink an LED in a pattern:
If the verification succeeds, the system proceeds to load and execute the c31bootbin. The system may log a message (often via a serial debug console) such as:
[INFO] c31bootbin verified successfully.
Starting bootloader...
If verification fails, the system typically halts, goes into a recovery mode, or displays an error (e.g., c31bootbin verification failed - System Halted).
The BootROM locates the c31bootbin binary at a predefined offset or partition (e.g., boot0 or boot1). In many designs, the bootbin is stored alongside its signature and a certificate chain.
