| Symptom | Likely Cause | Solution | |---------|--------------|----------| | CRC error after repack | Wrong offset or algorithm | Dump stock CRC location with IDA/Ghidra | | Signature mismatch | RSA‑2048 with Huawei private key | Patch bootloader or use known vulnerable version | | Bootloop after flash | Modified init scripts | Re‑extract stock, make minimal changes | | Fastboot not available | Bootloader locked | Unlock via vendor code or UART commands |
If you extracted a signature earlier, re‑append it: huawei s7721u recovery image verify failed repack
00000000 4e 41 4e 44 00 00 00 01 a5 3c 7f 88 00 00 00 20 |NAND.....<..... | | Symptom | Likely Cause | Solution |
A repacked image lacks the official Huawei private key signature. huawei s7721u recovery image verify failed repack
You cannot flash a repacked (un-signed) image unless your bootloader is explicitly unlocked .