Grub 2:2.06.r322.gd9b4638c5-1 won't boot and goes straight to the BIOS after update

Hi, having trouble arch-chrooting into my home directory in a LUKS encrypted vlume, the error I get is just that the directory /bin/bash can’t be found.
I mount the LUKS system as described
sudo cryptsetup open /dev/nvme0n1p2 mycryptdevice
sudo mount /dev/mapper/mycryptdevice /mnt
sudo mount /dev/nvme0n1p1 /mnt/efi
sudo arch-chroot /mnt
I then get the error message
“chroot: failed to run command ‘/bin/bash’: No such file or directory”
/bin/bash can be found at /mnt/@/bin/bash and I’ve tried copying it to /mnt/bin/bash and even /bin/bash but still the same error.
I’ve found running sudo arch-chroot /mnt/@ “works”, but I get the following error message as well
==> WARNING: /mnt/@ is not a mountpoint. This may have undesirable side effects.
Running grub-install then gives the error message:
grub-install: error: cannot find EFI directory.
Any help on what I’m doing wrong please? :sweat_smile: