Update erased custom uboot settings

This issue is probably related only to HBL.

After pkgupdate u-boot setting is erased. In case that user is booting from ssd/usb this can cause switch to emmc boot

pkgupdate output https://gist.github.com/BKPepe/e94be219949b4b4b5a506fe1ff2a52b3

Maybe related to https://gitlab.nic.cz/turris/turris-build/-/merge_requests/186