properly this time
Boot from archiso CD/DVD/USB
Prepare dir structire - in my case, it was:
mount /dev/nvme0n1p6 -o subvol=@ /mnt mount /dev/nvme0n1p1 /mnt/boot/efi
Hint: to find out proper patition names, you can use
Fix your problem!
Also see "10 use the power of arch-chroot when your computer crashes".
-o subvol=@ thingy to mount the proper subvol!
Otherwise, you'll have to
mount --bind /mnt/@ /mnt/@ before the second
grub-install won't find root filesystem in
and use proper path (
/mnt/@ instead of
/mnt) in the following commands