Fedora CoreOS: stuck on efi stub: exiting boot services

[Aegeontis]

1. Installed UEFI on an sdcard
2. Flashed a fedora coreos (arm64) image to a usb drive
3. As per the readme, manually edited the cmdline in grub and added acpi=off (for some reason the uefi settings refused to save that option 🤷).
4. Press f10 to boot
5. I get exactly the following output:

Booting a command list

EFI stub: Decompressing Linux Kernel...
EFI stub: Using DTB from configuration table
EFI stub: Exiting boot services...

6. The usb continues flashing (i.e. either something is writing to it or something is reading from it), but nothing further happens. I let it sit for at least 10 minutes, but still nothing.

[alsldlflglhljlk]

Try pressing F1 to enter the UEFI shell, then type fs0:, fs1:, fs2: etc until you find where your kernel is located. Then type:
.\kernelnamehere root=/dev/rootdevicehere rootwait ro and see what happens.

[Aegeontis]

For some reason I couldnt find the kernel and rootfs directly in any of the locations listed by map in the UEFI shell (only an EFI folder on fs0 with grub binaries). Therefore I did the following:

1. created a new usb drive from my desktop and manually copied just the rootfs.img and vmlinuz file (from the original fcos iso) to it.
2. Then I plugged it into the rpi, cd'd into it and ran .\vmlinuz root=./rootfs.img rootwait ro (I also tried .\vmlinuz root=.\rootfs.img rootwait ro, just in case)

Results are exactly the same as in my first message.

[alsldlflglhljlk]

The root argument should be what you expect the device to show up as in /dev, not a local file. If you are trying to load an initramfs, use initrd=initrdnamehere.img instead.

Try renaming vmlinuz to kernel8.img.efi and doing the same thing you did before, only invoking .\kernel8.img (not a typo, don't add the .efi) instead. If that works, the answer is simple – the kernel is not properly configured to support UEFI.

[Aegeontis]

The root argument should be what you expect the device to show up as in /dev, not a local file.

I dont quite understand what you mean by this. I have an iso file. Inside it is a rootfs.img file, a kernel and an initramfs (and some other files like grub). I dont have an unpacked/preinstalled root ready to go on my usb.

Afaik this should really matter though, as even without a rootfs or initramfs, the kernel should be able to at least print something?

Try renaming vmlinuz to kernel8.img.efi and doing the same thing you did before, only invoking .\kernel8.img (not a typo, don't add the .efi) instead.

Same results as before.

If you are trying to load an initramfs, use initrd=initrdnamehere.img instead.

I tried loading an initramfs too, but that did nothing more than adding EFI stub: Loaded initrd from command line option to the output.

If that works, the answer is simple – the kernel is not properly configured to support UEFI.

Could you specify what could be wrong with the kernel? The Fedora CoreOS docs say:

You can boot the live ISO in either legacy BIOS or UEFI mode, regardless of what mode the OS will use once installed.

fedora coreos docs