Booting Arch Linux with EFISTUB

· #linux
Booting Arch Linux with EFISTUB Booting Arch Linux with EFISTUB

UEFI (Unified Extensible Firmware Interface) is designed to streamline the boot process by allowing the system to boot directly into the operating system without the need for an intermediate bootloader such as GRUB. Using EFISTUB, you can configure your Arch Linux system to boot directly from UEFI by embedding the kernel and its parameters within a UEFI boot entry.

This approach will set up EFISTUB using the bcfg command available in UEFI Shell v2, accessible from an Arch Linux live ISO.

Step 1: Access the UEFI Shell

  1. Boot from your Arch Linux live USB or installation media.
  2. In the boot menu, choose UEFI Shell x86_64 v2.
  3. When the shell starts, press ESC to skip any startup scripts like startup.nsh

Step 2: Locate the EFI System Partition (ESP)

To identify where the EFI System Partition is mounted:

  1. Use the map command to list all storage devices:

    map

    Look for the partition labeled as FSX: (e.g., FS1:), which corresponds to your EFI System Partition.

  2. Verify its contents by listing the files:

    ls FS1:

    Replace FS1: with the correct identifier for your ESP.

Step 3: Add a boot entry for Arch Linux

  1. Identify the kernel file (vmlinuz-linux) and the initramfs file (initramfs-linux.img) on the ESP:

    ls FS1:\boot

    Adjust the path if the files are not in \boot.

  2. View the existing UEFI boot entries:

    bcfg boot dump

    Note the numbers to avoid conflicts with existing entries.

  3. Add a new boot entry pointing to the Arch Linux kernel. For example:

    bcfg boot add 0 FS1:\boot\vmlinuz-linux "Arch Linux"
    • 0 is the position in the boot menu. Adjust as needed.
    • Replace FS1:\boot\vmlinuz-linux with the correct path to your kernel.

  4. Add kernel parameters.

    bcfg boot -opt 0 "root=/dev/sda2 rw initrd=\boot\initramfs-linux.img"

    Adjust the root device (/dev/sda2) to match your system.

Step 4: Test your configuration

  1. Reboot the system to apply the changes:

    reset

  2. Remove the live media and verify if the system boots directly into Arch Linux.

Managing boot entries

  • To remove an existing boot entry:

    bcfg boot rm N

    Replace N with the index of the entry you want to remove (from bcfg boot dump).

  • To list entries again:

    bcfg boot dump

Troubleshooting

  • No Boot Entry: Ensure the kernel and initramfs paths are correct, and the ESP is mounted properly
  • Invalid PARTUUID: Double-check the UUID of your root partition using blkid
  • UEFI Shell Missing: Some systems don’t include a UEFI Shell by default. Use the Arch Linux live ISO or download the shell separately

Conclusion

With EFISTUB, you can streamline the boot process by directly booting into Arch Linux from the UEFI firmware, eliminating the need for GRUB or other bootloaders