GRUB error: unknown filesystem

Hey guys,
I’ve installed Manjaro XFCE and it worked fine. After restarting my PC, I cannot boot it anymore. Of course I already googled and found out that my grub installation is messed up but I’m too noobish to fix it myself.

Solution from another thread:

mount -t ext4 /dev/sda6 /manjaro
mount -t vfat /dev/sda1 /manjaro/boot/efi
mount --bind /dev /manjaro/dev
mount -t proc proc /manjaro/proc
mount -t sysfs sys /manjaro/sys
[ -d /manjaro/sys/firmware/efi/efivarfs ] || mkdir -p /manjaro/sys/firmware/efi/efivarfs
mount -t efivarfs efivarfs /manjaro/sys/firmware/efi/efivarfs
chroot /manjaro /usr/bin/bash
grub-install --recheck --no-rs-codes --modules="part_gpt part_msdos" --efi-directory="/boot/efi" --target="x86_64-efi"
umount -R /manjaro

Can I just apply the solution posted?

Some more info:

[manjaro ~]# lsblk -f
NAME        FSTYPE   FSVER            LABEL             UUID                                 FSAVAIL FSUSE% MOUNTPOINTS
loop0       squashfs 4.0                                                                           0   100% /run/miso/sfs/livefs
loop1       squashfs 4.0                                                                           0   100% /run/miso/sfs/mhwdfs
loop2       squashfs 4.0                                                                           0   100% /run/miso/sfs/desktopfs
loop3       squashfs 4.0                                                                           0   100% /run/miso/sfs/rootfs
└─sda1      ntfs                      HDD               66F63393F633630B                                    
sdb         iso9660  Joliet Extension MANJARO_XFCE_2122 2022-01-23-13-29-58-00                     0   100% /run/miso/bootmnt
├─sdb1      iso9660  Joliet Extension MANJARO_XFCE_2122 2022-01-23-13-29-58-00                              
└─sdb2      vfat     FAT12            MISO_EFI          01C9-8517                                           
├─nvme0n1p1 ntfs                      Wiederherstellung 94FA2D60FA2D403A                                    
├─nvme0n1p2 vfat     FAT32                              BA30-7E34                                           
├─nvme0n1p4 ntfs                      System            1674442574440A47                                    
├─nvme0n1p5 ext4     1.0                                308f23b4-27f4-4027-9d52-539174dddbaf                
└─nvme0n1p6 ntfs                                        3E6EB3C26EB3716F                                    

[manjaro ~]# test -d /sys/firmware/efi && echo efi || echo bios

Thanks in advance!

Why not try to use the tool created for the job?
manjaro-chroot -a

… and then fixing what you need to fix
and then updating grub

… and then fixing what you need to fix

What do I need to fix to get it running again?

Something like that?

manjaro-chroot -a
grub-install --recheck --no-rs-codes --modules="part_gpt part_msdos" --efi-directory="/boot/efi" --target="x86_64-efi"

This only for BIOS, not UEFI.

Not needed here. It is already included.

So, like here descibed: GRUB/Restore the GRUB Bootloader - Manjaro

manjaro-chroot -a
grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=Manjaro --recheck 
grub-mkconfig -o /boot/grub/grub.cfg

I don’t know.
You said:

so I assumed you knew.

No, something like what I wrote. :wink:
If you indeed want or need to to reinstall grub then I have to admit that I don’t know whether that command you found is correct.

something like

sudo manjaro-chroot -a
grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=manjaro --recheck --verbose
efibootmgr -v
exit ( quit chroot )