grub-install: error: unable to identify a filesystem.

howtoinstallgrub · 2022-07-05 19:29:32

I'm trying to install grub on a new laptop, and I have several issues and questions.
1. I've never dealt with GPT (on the pc I'm using I have dos) and I forgot to make a 1M partition for grub. So I made on and now it says
grub-install: error: unable to identify a filesystem in hostdisk//dev/sda; safety check can't be performed. I read somewhere that you don't need to format partition for grub and I couldn't find anything about it on wiki.
2. I saw an option in fdisk about making gpt -> dos. So the second question is it a good idea to change gpt to dos? Am I loosing anything? Also I don't see any info regarding installing grup on dos disklabel type. I do have it installed on this pc and I don't have any partitions for grub.

ewaller · 2022-07-05 19:44:51

A few things. First, welcome to the forums.

Is this a BIOS or a uEFI system? If it is a new (as in contemporary design) laptop, then it is most certainly uEFI. And, it follows that the drive will be GPT, not MBR.

A disk to be booted from uEFI (a GPT partitioned device) requires an EFI volume which must be vfat (well, not really, but for the purposes of this thread). That EFI volume should be a couple hundred megabytes.
The uEFI firmware knows how to find and read that volume. Unlike the old MBR, you do not install GRUB to the disk (I presume you tried because of the /dev/sda message). You install it to the EFI volume.

Do not change back to MBR from GPT. You will not be able to boot it from uEFI and will have to use a legacy boot setting in your motherboard firmware (if it even supports it).

Read the following: https://wiki.archlinux.org/title/GRUB#UEFI_systems Ignore portions of that article that refer to BIOS.

As an alternative (and I just did this this weekend with my new system), consider ditching the bootloader and using uEFI to directly boot your kernel: https://wiki.archlinux.org/title/EFISTUB

Last edited by ewaller (2022-07-05 19:45:43)

howtoinstallgrub · 2022-07-05 20:00:36

ewaller wrote:

A few things. First, welcome to the forums.
Is this a BIOS or a uEFI system? If it is a new (as in contemporary design) laptop, then it is most certainly uEFI. And, it follows that the drive will be GPT, not MBR.
A disk to be booted from uEFI (a GPT partitioned device) requires an EFI volume which must be vfat (well, not really, but for the purposes of this thread). That EFI volume should be a couple hundred megabytes.
The uEFI firmware knows how to find and read that volume. Unlike the old MBR, you do not install GRUB to the disk (I presume you tried because of the /dev/sda message). You install it to the EFI volume.
Do not change back to MBR from GPT. You will not be able to boot it from uEFI and will have to use a legacy boot setting in your motherboard firmware (if it even supports it).
Read the following: https://wiki.archlinux.org/title/GRUB#UEFI_systems Ignore portions of that article that refer to BIOS.
As an alternative (and I just did this this weekend with my new system), consider ditching the bootloader and using uEFI to directly boot your kernel: https://wiki.archlinux.org/title/EFISTUB

Thanks for answering.
It's BIOS. Arch offers bios when I begin installation (it's an old Thinkpad t420). I don't have /sys/firmware/efi either.

Last edited by howtoinstallgrub (2022-07-05 20:06:28)

ewaller · 2022-07-05 20:05:18

Then why are we talking GPT? Yes, you can change over to an MBR drive.

howtoinstallgrub · 2022-07-05 20:08:50

ewaller wrote:

Then why are we talking GPT? Yes, you can change over to an MBR drive.

I though about that and tried running "sgdisk -m /dev/sda". Nothing changes. I saw an option in fdisk - changing gpt to dos and I though about that too and that was my second question. Is it a good idea to do this?
Also, this ssd used to have win10 installed, if that's important.

Last edited by howtoinstallgrub (2022-07-05 20:20:45)

howtoinstallgrub · 2022-07-05 21:22:31

I rephrase second question. I can change gpt to dos in fdisk. But how do I install grub in that case? I only see guide about MBR and GPT. when I do grub-install what should I place after "target", root_partition?

seth · 2022-07-05 21:39:24

For "Disklabel type: dos" follow the MBR instructions.

Arch Linux

#1 2022-07-05 19:29:32

grub-install: error: unable to identify a filesystem.

#2 2022-07-05 19:44:51

Re: grub-install: error: unable to identify a filesystem.

#3 2022-07-05 20:00:36

Re: grub-install: error: unable to identify a filesystem.

#4 2022-07-05 20:05:18

Re: grub-install: error: unable to identify a filesystem.

#5 2022-07-05 20:08:50

Re: grub-install: error: unable to identify a filesystem.

#6 2022-07-05 21:22:31

Re: grub-install: error: unable to identify a filesystem.

#7 2022-07-05 21:39:24

Re: grub-install: error: unable to identify a filesystem.

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