I don't know if this is the cause of the issue you've reported or not, but when preparing your chroot you need to mount /sys using "--rbind" rather than "--bind", to include the mount at /sys/firmware/efi/efivars in the chroot.
"--rbind" would also be recommended on the /dev bind, to include /dev/pts in the chroot. On Mon, Dec 1, 2025 at 8:58 AM Javi Jap via Support requests for the GRand Unified Bootloader <[email protected]> wrote: > Hi, > I'm running Ubuntu 22.04 in a HDD (/dev/sdd) and I have a 2T SSD disk > (/dev/sdb) where I have another ubuntu installed and that is partitioned > like this: > > $ sudo gdisk -l /dev/sdbGPT fdisk (gdisk) version 1.0.8 > Partition table scan: MBR: protective BSD: not present APM: not > present GPT: present > Found valid GPT with protective MBR; using GPT.Disk /dev/sdb: 3907029168 > sectors, 1.8 TiBModel: Samsung SSD 870 Sector size (logical/physical): > 512/512 bytesDisk identifier (GUID): > C04E1719-7349-4D27-BB25-B8FDF867C2C1Partition table holds up to 128 > entriesMain partition table begins at sector 2 and ends at sector 33First > usable sector is 34, last usable sector is 3907029134Partitions will be > aligned on 2048-sector boundariesTotal free space is 4205 sectors (2.1 MiB) > Number Start (sector) End (sector) Size Code Name 1 > 2048 1015807 495.0 MiB EF00 EFI system partition 2 > 1015808 3112959 1024.0 MiB 8300 Linux filesystem 3 > 3112960 259753983 122.4 GiB 8300 Linux filesystem 4 > 259753984 3869278207 1.7 TiB 8300 Linux filesystem 5 > 3869280256 3907028991 18.0 GiB 8200 > > > sdb2 is the boot partition, and sdb3 and sdb4 root and home respectively. > > The EFI partition (/dev/sdb1) has boot and esp flags: > $ sudo parted /dev/sdb print Model: ATA Samsung SSD 870 (scsi) Disk > /dev/sdb: 2000GB Sector size (logical/physical): 512B/512B Partition Table: > gpt Disk Flags: > Number Start End Size File system Name > Flags 1 1049kB 520MB 519MB fat32 EFI system partition > boot, esp 2 520MB 1594MB 1074MB ext4 Linux > filesystem 3 1594MB 133GB 131GB ext4 Linux > filesystem 4 133GB 1981GB 1848GB ext4 Linux > filesystem 5 1981GB 2000GB 19,3GB linux-swap(v1) > swap > > When I try to install grub in that partition it fails with the error: > > grub-install: error: unknown filesystem. > > > I've seen other people say that this is solved by disabling the > metadata_csum_seedfeature but in my case that doesn't solve the issue. > To install grub in /dev/sdb I mount root (/dev/sdb3) in /mnt, then I mount > boot partition in /mnt/boot and efi partition in /mnt/boot/efi. Then I bind > my running ubuntu's dev, proc and sys with the mounted root and chroot to > it. When I execute grub-installcommand to install grub it fails with the > error mentioned before: > $ sudo mount /dev/sdb3 /mnt/$ sudo mount /dev/sdb2 /mnt/boot/$ sudo mount > /dev/sdb1 /mnt/boot/efi/$ sudo mount --bind /dev /mnt/dev$ sudo mount > --bind /proc /mnt/proc$ sudo mount --bind /sys /mnt/sys$ sudo chroot > /mntroot@LINUX-WS:/# grub-install --target=x86_64-efi > --efi-directory=/boot/efi --bootloader-id=GRUBInstalling for x86_64-efi > platform.grub-install: error: unknown filesystem. > if I run the grub-install command with high verbosity (-vv) I get a Read > out of rangeerror before failing, maybe this is a hint of what it is > happening but I have no idea. > > root@LINUX-WS:/# grub-install --target=x86_64-efi > --efi-directory=/boot/efi --bootloader-id=GRUB > -vv[...]grub-core/kern/fs.c:56: Detecting > cbfs... grub-core/kern/disk.c:420: Read out of range: sector 0x200000 > (attempt to read or write outside of partition). grub-core/kern/fs.c:78: > cbfs detection failed. grub-core/kern/fs.c:56: Detecting > btrfs... grub-core/kern/fs.c:78: btrfs detection > failed. grub-core/kern/fs.c:56: Detecting bfs... grub-core/kern/fs.c:78: > bfs detection failed. grub-core/kern/fs.c:56: Detecting > afs... grub-core/kern/fs.c:78: afs detection > failed. grub-core/kern/fs.c:56: Detecting affs... grub-core/kern/fs.c:78: > affs detection failed. grub-install: error: unknown filesystem. > > Any help will be much appreciated! > >
