Occationally grub doesn't seem to work properly because of a Windows update or grub was not properly installed during Parrot's install and so on.
1) The first step is to boot live using a bootable USB key of Debian or ParrotOS. Boot on it, and then open a terminal.
2) In the terminal type:
sudo -i fdisk -l
The fdisk command will show your partition scheme, you have to identify 2 things (only one for those using legacy instead of uefi)
- The partition that contain the "/" which is the partition where the system is installed.
- The EFI partition
Let's say my system partition is
/dev/sda2 and my EFI partition is
/dev/sda1. Your partition "name" might be different (e.g.nvme01 etc), just replace mine with yours in the command shown below.
3) Now you have to mount the partitions
mount /dev/sda1 /mnt mount --bind /proc /mnt/proc mount --bind /sys /mnt/sys mount --bind /dev /mnt/dev
Those that have Legacy instead of EFI can go to step 4)
For EFI there is one extra step: Mount your EFI partition
mount /dev/sda1 /mnt/boot/efi
Sometimes errors like this can result:
mount: /mnt/boot/efi: mount point does not exist.
To solve it create the efi directory in
/mnt/boot/ using this command:
then try to mount the efi partition again.
4) Now we have to chroot into the system
Now that you are in you can just install the grub by typing the command below (grub-install will ask for the disk, not a partition so don't put any number like this: sda instead of sda1
Then if no errors are found you can just exit by typing:
and reboot the system. Once the system is rebooted, run
update-grub to be sure that any other OS is detected by the grub.
Written by KileXt
If you run into any issues please post in support on the forum.