# Crate a 1GB efi partition
parted /dev/nvme0n1 ...

# Mark it as boot and esp
parted /dev/nvme0n1 set X esp on

# It should look like that in the end:
(air) [~] parted /dev/nvme0n1 print
Model: APPLE SSD AP0512Q (nvme)
Disk /dev/nvme0n1: 500GB
Sector size (logical/physical): 4096B/4096B
Partition Table: gpt
Disk Flags:

Number  Start   End    Size    File system  Name                  Flags
...
 6      403GB   404GB  1074MB  fat32                              boot, esp
...

mkfs.vfat /dev/nvme0nX

mkdir /boot/efi

# Put that in /etc/fstab:
/dev/nvme0n1p6 /boot/efi vfat defaults 0 0

mount /boot/efi

apt-get install grub-efi

update-grub
dpkg-reconfigure grub-efi-arm64
# When prompted for 'Force extra installation to the EFI removable media path?', say yes.
# See also: https://wiki.debian.org/UEFI#Force_grub-efi_installation_to_the_removable_media_path
# There are also reports for manjaro that required grub-install --removable /dev/nvme0nX
# At the end you need this file (capitalization does not matter) for u-boot to pick up grub: /boot/efi/EFI/BOOT/BOOTAA64.EFI

# Now Debian install a file called fbaa64.efi. Delete it otherwise, u-boot will be unable to boot grub:
find /boot/efi -name fbaa64.efi | xargs rm

# I compiled u-boot on aarch64 linux:
git clone https://github.com/kettenis/u-boot
cd u-boot/
git checkout apple-m1-m1n1-nvme
make apple_m1_defconfig
make
cd ..

# Also build m1n1
git clone --recursive https://github.com/AsahiLinux/m1n1.git
cd m1n1
make -j
cd ..

# Concat u-boot. It incldues the dtb for all suppported models
cat m1n1/build/m1n1.macho `find u-boot -name \*.dtb` u-boot/u-boot-nodtb.bin > u-boot.macho

# Upload u-boot.macho somewhere

# Boot into recovery

# download the file

# run

kmutil configure-boot -c u-boot.macho -v /Volumes/Linux

Tripwires:

# 17:28 < kov> Glanzmann, so, fun discovery, removing this file makes it work it seems fbaa64.efi