* What I did was the above, I partitioned the USB as follows:

>parted --script /dev/sda mklabel gpt
parted --script --align=optimal /dev/sda mkpart ESP fat32 1MiB 551MiB
parted --script --align=optimal /dev/sda mkpart NAME ext4 552 MiB 100%
parted --script /dev/sda set 1 boot on
mkfs.vfat -n ASAHI /dev/sda1
mkfs.ext4 /dev/sda2

Then I git cloned the alarm-builder and set ROOT_UUID and EFI_UUID to the USB UUIDs (`lsblk -o name,uuid,fstype,mountpoint` gives info) in `build.sh`. I also removed building asahi-desktop and uefi-minimal to save time.

Then I mounted sda1 onto mnt and copied the EFI folder (under /esp/ in the images/asahi-base directory of the asahi-alarm-builder directory) onto sda1. After this I unmounted sda1 and replaced it with sda2 on mnt, mounted the root.img locally onto a directory in Desktop to make sure I'm using the proper build data and copied those contents onto sda2.

After setting up as such it booted but now I'm looking why it's throwing me a user name / password screen.