uefi boot from SD card, nixify uefi bootloader

[adminy]

Just wondering if its possible to create an SD card that contains the UEFI bootloader on SD card instead?

This way the output can also be nixified. No manual steps afterwards would be required.

[ryan4yin]

It's possible, edk2-rk3588 says that:

If you wish to have both UEFI and an OS on the same SD or eMMC device: flash UEFI first, then create any additional partitions without touching the first, reserved one. Steps for updating the firmware in this case can be found here.

[cessationoftime]

After flashing edk2-rk3588 from armbian on my SD card, I wrote the rawEfiImage-opi5plus straight to my SD card without much trouble. I booted from that, built a native image locally and wrote that image to my SSD, expanding the partition with parted.

So you should be able to use the rawEfiImage on an SD card (assuming that is what you mean). I did encounter warning spam, (#37) when I did this. But I silenced them, built a native image and wrote it to the SSD, this got rid of (#37) and I could boot from SSD with UEFI.