rk3588 MNT Reform2 fails to boot from SD card

Vagrant Cascadian
2026-01-30T01:47:01Z

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Thanks for adding support for rk3588 MNT Reform2!

I tried using u-boot 2026.01 with the rk3588 MNT Reform2, but it only
gets as far as SPL, and then fails:

U-Boot SPL 2026.01 (Jan 01 1970 - 00:00:01 +0000)
Trying to boot from MMC1
mmc_load_image_raw_sector: mmc block read error
Error: -38
SPL: Unsupported Boot Device!
SPL: failed to boot from all boot devices
### ERROR ### Please RESET the board ###

I *think* MMC1 is eMMC, which I currently have blanked, as recovering
from a failed install on eMMC is trickier.

The vendor u-boot works fine on either eMMC or SD.

Any suggestions to get it to support booting off SD card?