@mckinley@mckinley.cc It booted. I was going to do more but I had actual work to do so I shelved it. Maybe I’ll come back to it another time. These drives are in really bad shape, though. They hold up udev by 30-60 seconds on every boot, even when booting the Arch install ISO, covering the console with lots of SATA errors and timeouts I don’t really understand.
Badblocks via mkfs.ext4 -cc was taking too long on the full 1+1 TB array so I made new 250 GB partitions and neither drive had bad blocks in that range so it was just a waste of time. Maybe if I come back to it I’ll do the full array and have the EFI system partition in RAID 1 just for fun. I didn’t know that worked with software RAID.
The key part is to use –metadata 1.0 in order to keep the RAID metadata at the end of the partition, otherwise the firmware will not be able to access it.
I had the ESP on a USB stick for simplicity’s sake.