Booting from an SD card on a Pi 4 Aarch64

[goverp]

My apologies if this has been beaten to death already, but if so, I blame Google for not finding the answer to my problems.

I've run this Pi4 as an ARMv7 installation for ages, but an update a few months back gave a message saying that kernel would no longer work and I had to migrate to the Aarch64 setup. So I carefully followed the instructions on
[url]https://archlinuxarm.org/platforms/armv8/broadcom/raspberry-pi-4[/url],
taking care to pick up the changes for Aarch64, stuck the resulting SDcard in my Pi, and booted.

It dies with messages:
[quote]Dependency check failed for file system check on /dev/disk/by-partuuid/00000000-02
...
root account is locked
Press Enter to continue[/quote]

I found various posts for these symptoms, and mostly they lead to either futile attempts to edit /etc/fstab or instructions to update the UBoot configuration in /boot/boot.txt.

I thought a bit harder, and realised the issue was not that the partuuid was wrong anywhere, it was that an SDcard, or indeed
[b]any drive formatted with an MBR partition table does not have partuuids.[/b] They need a GPT partition table.

I ran gdisk against my card to convert it - that complained that the last partition would be crunched, but that was OK as it was swap space, so I deleted it, ran gdisk, then recreated that final swap partition. I also updated /etc/fstab in the root partition to use the boot partition's PARTUUID (from blkid).

That worked. The Pi 4 now boots fine.

Therefore, the instructions on [url]https://archlinuxarm.org/platforms/armv8/broadcom/raspberry-pi-4[/url] need updating to make it clear you need to make a GPT partition table; an MBR one won't work.

As an aside, I'm an enthusiast for F2FS, so I made another SD card with an f2fs root partition
(as per [url=https://wiki.archlinux.org/title/F2FS#Creating_a_F2FS_file_system]the Arch wiki item[/url])
and a GPT partition table. That also booted without problem. (Well, it was an old card, and I got messages about checkpoints being suspended for too long that I think are down to the fact that this particular SD card has been written to rather a lot).