Huawei S7721u Recovery Image Verify Failed Repack -

Access UART or JTAG, halt boot, modify DTB or bootloader env:

# In bootloader prompt
setenv verify_recovery 0
saveenv
reset

Or hex‑patch bootloader.img:

binwalk recovery_stock.img
# Look for: signature footer, RSA keys, or CRC32 at end

Common locations:

Use hexdump to inspect:

hexdump -C recovery_stock.img | tail -n 32

Via fastboot (if available):

fastboot flash recovery recovery_new.img
fastboot reboot

Via TFTP recovery mode:

Mount & edit:

mkdir /mnt/recovery
sudo mount -o loop recovery_nosig.img /mnt/recovery
# Replace files, add scripts, etc.
sudo umount /mnt/recovery

Users repack the firmware to:

Run:

hexdump -C original_recovery.img | head -40

You should see something like:

00000000  4e 41 4e 44 00 00 00 01  a5 3c 7f 88 00 00 00 20 |NAND.....<..... |

Or a Huawei-specific header:

00000000  48 55 41 57 45 49 00 01  00 00 1c 20 00 00 00 10 |HUAWEI..... ....|

Critical: The first 4 bytes (HUAW or NAND) define the image type. If you repack without preserving this, verification fails.

The S7721U is a carrier‑grade device – its verification is often stronger than consumer routers. If you cannot patch the bootloader, consider: huawei s7721u recovery image verify failed repack

For further assistance, provide:

To understand the error, you must understand the boot process: