[U-Boot] Integity validation (checksum) of a squashfs root file system

[Pascal Levesque]

Hi,

I would like to validate the integrity (checksum) of a squashfs root file system before starting Linux.

Current strategy I am using is:
- Wrap squashfs rootfs inside a u-boot image
- TFTP download on the target
- Download validation using iminfo
- Save squashfs rootfs in flash without the image header (Linux failed to load squashfs rootfs if u-boot image is present)

Problems:
- I need to hardcode squashfs rootfs offset in u-boot image in order to be able to flash it
- U-Boot image header information (size, crc, ...) is lost after a reboot. It is not possible to check the integrity of the flash content.

I would like to save some fields of u-boot image header (size, crc, ...)  in u-boot environment variables. And then do an integrity check at boot time.

I have not find a way to extract those fields and save them without changing u-boot code. 
I have added some code to “iminfo” command to set environment variables for CRC, size, payload offset, timestamp.

Is it an acceptable way of doing it?
Is there a better way of doing it?

Thanks in advance,

Pascal