Huawei S7721u Recovery Image Verify Failed Repack Guide

If the bootloader strictly enforces RSA signatures, you have two choices:

Why "verify failed" happens (causes)

binwalk -e original.bin

Repacking the Huawei S7721U recovery image is not a hack in the pejorative sense; it is a disciplined engineering response to a system that prioritizes integrity over flexibility. The "verify failed" error is a feature, not a bug. Successfully repacking requires intimate knowledge of the device's boot chain, cryptographic primitives, and filesystem layouts.

: Manual repacking often alters the exact block sizes, offset locations, or file headers specified in the system partition table, triggering an automatic safety rejection by the BootROM. huawei s7721u recovery image verify failed repack

The Huawei S7721U often features secondary flash or CF card options depending on the main processing unit chassis setup.

Or hex‑patch bootloader.img :

Once you have repacked the recovery image, follow these steps to flash it onto the switch: