Fixing the ‘Executing grub-install /dev/sda Failed’ Error When Installing GRUB

Understanding GRUB Bootloader Installation

GRUB (Grand Unified Bootloader) is the most commonly used bootloader on Linux. It loads the Linux kernel into memory so the operating system can start. The grub-install command is used to install the GRUB files onto the system’s storage device, usually into the MBR (Master Boot Record) or a dedicated boot partition.

A typical grub-install command looks like:

grub-install /dev/sda

This installs GRUB onto the /dev/sda device. If this installation fails with an error, the system won’t be bootable. Let’s go through some troubleshooting steps.

Step 1: Verify the Correct Install Target Device

The first thing to check is whether you specified the correct target drive device for grub-install. Using the wrong drive will obviously result in failure.

Verify the Linux system drive with:

df /boot

Or:

findmnt / -o SOURCE

This prints the actual drive Linux is installed on, usually sda, nvme0n1, vda etc. Rerun grub-install with the correct device name:

grub-install /dev/sda

If still failing, the issue is something other than the wrong target drive.

Step 2: Check for UEFI vs BIOS Booting

GRUB installation is different for UEFI and legacy BIOS systems. An issue here can cause problems.

First determine your firmware type:

ls /sys/firmware/efi

If this folder exists, you have UEFI. BIOS systems will show standard directories like /boot instead.

For UEFI installs, you need to point grub-install to the EFI partition instead of the full drive. Get your ESP partition with:

fdisk -l

Then install to that, like:

grub-install /dev/sda3

For BIOS ensure you are installing GRUB to the full drive like /dev/sda, not a single partition.

Use the appropriate grub-install command for your firmware.

Step 3: Check for Unsupported Filesystems

GRUB requires support for the filesystem used by the /boot partition in order to install properly.

Filesystems like EXT2/3/4, BtrFS and XFS are supported. But ZFS, ReiserFS or other experimental filesystems can cause issues.

Verify your /boot partition filesystem:

df /boot

Or:

findmnt /boot -o FSTYPE

If using an unsupported filesystem for boot, you’ll need to reformat to a compatible one before GRUB can install.

Step 4: Make Sure /boot Partition Has Enough Space

GRUB requires at least 100MB of free space at /boot to install properly.

Check your current available space:

df -h /boot

If /boot is full or near capacity, expand it or clear space before trying grub-install again.

Having sufficient free space is critical.

Step 5: Disable Secure Boot (UEFI Only)

For UEFI systems, having Secure Boot enabled can interfere with GRUB installing properly.

Enter your BIOS/firmware settings and disable Secure Boot, then try grub-install again.

Once GRUB is installed, you can re-enable Secure Boot if needed.

Step 6: Ensure Software RAID Arrays Are Assembled

If using Linux software/fake RAID with mdadm, the arrays need to be assembled before grub-install can succeed.

Assemble any RAID devices like /dev/md0 with:

mdadm --assemble --scan

Then reattempt installing GRUB.

Step 7: Update GRUB Package and Configuration

An outdated GRUB package or broken configuration can also cause issues.

Update GRUB and regenerate configs:

sudo apt update
sudo apt install --reinstall grub-common grub-pc-bin grub-pc
sudo update-grub

Or on RPM distros:

sudo yum update grub2-common grub2-tools-extra grub2-tools
sudo grub2-mkconfig -o /boot/grub/grub.cfg 
sudo grub2-install /dev/sda

Refreshing the GRUB install often fixes various errors.

Step 8: manually walk through grub-install Steps

As a last resort, you can manually perform each step of grub-install:

• Ensure boot partition is mounted
• Bind mount key filesystems like /dev, /proc, /sys
• Check that boot directory exists
• Run grub-mkimage to generate GRUB images
• Use grub-setup to install images to boot record

Walking through the manual install steps can help isolate any specific points of failure.

Summary of Resolutions

To summarize, fixing the ‘grub-install failed’ error involves:

1. Specifying the correct drive/partition to install to
2. Using proper UEFI vs BIOS grub-install commands
3. Ensuring filesystem compatability for /boot
4. Checking for sufficient free space at /boot
5. Disabling Secure Boot (UEFI only)
6. Assembling any required software RAID devices
7. Updating/reinstalling GRUB packages
8. Performing manual grub-install steps

Running through this checklist will help identify and correct the underlying issue so GRUB can fully install.

Key Takeaways for Debugging GRUB Installation

To recap, focus on these areas when troubleshooting GRUB failures:

• Double check drive and partition paths
• Handle differences between UEFI and BIOS
• Verify a compatible /boot filesystem
• Check for space constraints at /boot
• Disable Secure Boot if needed
• Assemble software RAID volumes
• Refresh GRUB packages and configuration
• Perform manual grub-install steps

Keeping these guidelines in mind will allow you to systematically isolate the cause of ‘grub-install failed’ errors and get GRUB installed successfully.

Conclusion

While vague installation errors make debugging tricky, methodically checking partition configurations, filesystems, boot modes, device paths, and software RAID volumes enables isolating the underlying GRUB issue.

Combining package updates with manual procedures provides the knowledge to overcome cryptic ‘grub-install failed’ problems and get your system booting properly again. With the right troubleshooting technique, you can confidently recover from GRUB installation failures.