Translations:GRUB/Restore the GRUB Bootloader/9/en
Manual chroot
Mount the partitions using the designated temporary mountpoint and always start with root
root # mount /dev/sdyC /mnt
Then - if applicable - mount boot
root # mount /dev/sdyB /mnt/boot
Then - if applicable - mount efi
root # mount /dev/sdyA /mnt/boot/efi
Create the chroot environment and use bash as shell
root # manjaro-chroot /mnt /bin/bash