How to Fix Bazzite Boot Error with Bad Shim Signature

If you recently installed Bazzite OS to escape the disaster that Windows is becoming only to get the "Bad Shim Signature" boot error. It means that the system is having trouble verifying the bootloader and kernel due to Secure Boot or EFI issues. So follow along as we guide you through all the steps you need to follow in order to solve the problem.

Bazzite Boot Error with Bad Shim Signature

The full error reads as follows:

This error occurs in systems using EFI and Secure Boot. EFI is a modern system firmware interface, and Secure Boot is a security feature that ensures only trusted software is loaded during boot. The messages indicate two main issues:

• bad shim signature means that the bootloader or kernel signature could not be verified by Secure Boot. This usually happens when the software is not signed with a key recognized by the firmware.
• you need to load the kernel first indicates that the bootloader could not locate or authenticate the kernel image.

Disable Secure Boot

To determine if Secure Boot is the cause, you can temporarily disable it. Since pretty much every single computer and motherboard manufacturer has completely different BIOS and UEFI system it is impossible for us to show you the exact process here. You should also know that disabling Secure Boot will prevent you from playing some some games that require it to be enabled for Anti-Cheat software to work. Without it it will fail.

• Reboot the system and enter the BIOS or UEFI setup. This is usually done by pressing keys such as F2, F10, Delete, or Esc during startup.
• Locate the Secure Boot option in the firmware menu.
• Set Secure Boot to Disabled.
• Save the changes and exit the firmware.
• After disabling Secure Boot, attempt to boot again. If the system starts successfully, the problem is related to signature verification.

Reinstall or Repair the Bootloader

If the above step didn't work you might have to reinstall or repair the boot loader.

• Boot the system from a live USB or recovery disk for your operating system.
• Mount the EFI system partition, usually at /boot/efi.
• Reinstall the GRUB bootloader. This can often be done using commands like grub-install and update-grub for Linux systems.
• Ensure that the GRUB configuration points to the correct kernel and initramfs images.

Verify Kernel and Bootloader Signatures

If you want to use Secure Boot, you must ensure that the bootloader and kernel are properly signed. This might not be possible on all devices.

• Use the sbverify tool to check the signature of the bootloader and kernel files.
• If files are unsigned, either enroll the key used to sign them in the firmware or obtain signed versions from your distribution.
• Regenerate the GRUB configuration after ensuring all components are signed correctly.

Check EFI Partition Integrity

An incorrect EFI partition layout can prevent the system from booting:

• Verify that the EFI system partition is mounted at /boot/efi.
• Ensure that it contains the correct directories for the bootloader.
• Repair the partition if it is corrupted, possibly using filesystem repair tools such as fsck for FAT32 partitions.

Update Firmware and Bootloader

Older firmware may have compatibility issues:

• Check your motherboard or system manufacturer for the latest BIOS or UEFI firmware updates.
• Update the firmware according to the manufacturer instructions.
• Update your bootloader package to the latest version provided by your distribution.

Re-enable Secure Boot Carefully

Once the bootloader and kernel are properly signed, you can re-enable Secure Boot:

• Enter firmware settings and enable Secure Boot.
• Verify that the system still boots correctly.
• If issues reappear, repeat the signature verification steps and ensure keys are enrolled correctly.