I'm running Armbian off NVMe, and flashed the U-Boot SPI firmware (u-boot-sunxi-with-spl.bin → /dev/mtdblock0) so I no longer need an SD card inserted just to get it booting. That part works great. But now I'd like to be able to pop in an SD card occasionally to try other distros/images without disturbing my NVMe install — and it seems that's not currently possible: with an SD card inserted, the board still boots straight from NVMe and ignores the card entirely.

Dug into it a bit over serial console:

The default boot_targets is fel nvme0 mmc_auto usb0 pxe dhcp — NVMe is checked before the SD/eMMC. Radxa hit the same issue on the RK3588 boards and fixed it upstream (radxa/u-boot#25, "give SD higher boot priority than NVME"). Would be great to see the same fix applied here.

I tried working around it manually (setenv boot_targets 'mmc0 mmc1 nvme0 usb0 pxe dhcp'), which does work for that boot — SD is picked up correctly when present. But saveenv fails with "Unable to use mmc 0:1... Failed (1)", so the change doesn't survive a reboot. Looks like this build uses CONFIG_ENV_IS_IN_FAT targeting mmc 0:1, but the Armbian SD image ships a single ext4 partition there (confirmed with fstype mmc 0:1 → ext4), so the environment can never actually be saved.

Is this a known limitation, or is there a recommended way to get persistent SD-over-NVMe priority on this board right now?

Hi,

 

you could try to apply the patch yourself (radxa patch that changes the boot order), then re-build u-boot:
 

./compile.sh BOARD=<your board> BRANCH=current BUILD_ONLY="u-boot"

 

Then flash again the new binary on  /dev/mtdblock0

Thanks IBV, Just got your post. I'll give it a try.