Note: The installer includes semi-automated UEFI installation. This article concerns manual installation.As Arch-wiki entries are some times too theoretical and offer little practical solution assistance, and since booting uefi systems has caused a headache to users in most linux installations, we dedicate this section as a supplement to the Arch entry. The article is a generous contribution by an Obarun community member marianarlt who has developed a high level of expertise in setting up the bootloader for various UEFI capable or non-Bios systems. In addition an important amendment and bug discovery, in relation to mounting efivarfs, was made by techore in this forum thread.
As with any other manual you should first read the whole text with attention and then apply the content. When installing Obarun to boot with UEFI make sure you boot your live medium accordingly.
`sudo obarun‑install` you want to make sure the above requirements are satisfied and you made up your mind about any optional steps. Your installation disk is most probably going to be sda but you should make sure with
The most minimal layout for Obarun on UEFI could be as follows:
More realistically you may want to do something similar to the following though:
Your actual needs may differ and layouts and formats may be changed to accomodate those needs as mentioned before. This example is a tried and safe, easy to configure and maintain, layout. The following instructions will therefore apply to this example. Please inform yourself well when choosing different file systems and layouts, including encryption.
`oblive` and password
`sudo gdisk /dev/sda`
ENTER then for the ending sector type
`+550M` and confirm.
`ef00` and confirm.
ENTER then for the ending sector type
`+2G` and confirm.
`8200` and confirm when prompted for the identifier.
`n` and by now you get the idea, make it the size you want for your root partition.
`8304` which stands for: Linux x86‑64 root (/).
`8302` which stands for: Linux /home.
`w`. You will exit out of gdisk.
`sudo mkfs.vfat -n ESP /dev/sda1`
`sudo mkswap -L SWAP /dev/sda2`
`sudo mkfs.ext4 -L ROOT /dev/sda3`
`sudo mkfs.ext4 -L HOME /dev/sda4`
`sudo mount /dev/sda3 /mnt`
`sudo mkdir /mnt/boot && mount /dev/sda1 /mnt/boot`
`sudo mkdir /mnt/efi && mount /dev/sda1 /mnt/efi`
`sudo mount /dev/sda4 /mnt/home`
`sudo swapon /dev/sda2`
# mount -t efivarfs efivarfs /sys/firmware/efi/efivars
`yes` when prompted.
`Launch a shell on /mnt (7)`. This will chroot you into your install and let you install additional packages.
For the sake of simplicity it is, for now, discouraged to use syslinux for booting layouts other than BIOS/MBR.
This manual provides two easy to set up options for booting a UEFI/GPT scheme for you to choose from.
Now that you know about both it is up to you to decide. They are both easy to set up.
Note: Make sure to finish the installation as outlined in the Step by Step section and that you are not inside of the obarun-install script!
`sudo efibootmgr -c -d /dev/sda -p 1 -L "Obarun" -l \vmlinuz-linux -u "root=LABEL=ROOT ro resume=LABEL=SWAP quiet initrd=\intel-ucode.img initrd=\initramfs-linux.img"`
From here on whenever you want to change the boot entry you would want to delete the existing one with
`sudo efibootmgr -b 0000 -B` where
0000 must match your Obarun entry and then recreate it with the above command. Refer to the provided links for more details.
`sudo arch-chroot /mnt`
`pacman -S grub`
`grub-install --target=x86_64-efi --efi-directory=/efi --bootloader-id=grub`
`grub-mkconfig -o /boot/grub/grub.cfg`
From here on whenever you want to change the boot entry you would want to edit /etc/default/grub and/or the scripts in /etc/grub.d/ and rebuild with the command from step four. Refer to the provided links for more details.
As you see the complicated part with bootloaders in general is the system setup itself. Instructing the bootloader can be a one liner in an UEFI configuration. The Obarun team hopes that this was of help to you. Further information and discussion can be found in the Obarun Forums.
 To boot your live media in UEFI mode go into your motherboards boot menu after pressing the power button on your PC. This is specific to your motherboard and often shows briefly on the first screen that appears after pressing the power button. Most times it is one of the function Keys F1‑F12. Inside your motherboards boot menu choose to run your live medium with UEFI. The entry will literally say "UEFI" and the device name (most probably a USB flash drive).
If after booting your live medium you're still unsure you may issue
`ls /sys/firmware/efi/efivars`. If booted in UEFI mode this command will print a lot of names with long numbers else it will print nothing.
 Don't go smaller on the size for your EFI system partition. It is unnecessary with todays disk sizes and may cause confusion and bugs in older EFI implementations. To learn more about EFI/UEFI in general refer to the very in depth and excellent articles written by Rod Smith, the creator of rEFInd: https://www.rodsbooks.com/efi-bootloaders/principles.html
 Arch is deprecating the mount point /boot/efi for the ESP in favor of /efi. See https://wiki.archlinux.org/index.php/EFI_system_partition#Mount_the_partition.
It is important to realize that the actual mount point of the ESP does not matter in terms of how the UEFI functions. The ESP will always be searched by the UEFI no matter the mount point, for the EFI application to boot from. The only importance of the mount point is when configuring the bootloader. The mount point of the GRUB EFI application is passed to the NVRAM entry. That then gets booted by the UEFI which then in return chain loads itself into the vmlinuz-linux EFI application. EFISTUB uses /boot for convenience as the EFI bootloader will get configured to directly boot the vmlinuz-linux EFI application from that default location.
 The UEFI specification mandates support for the FAT12, FAT16, and FAT32 file systems (see UEFI specification version 2.8, section 18.104.22.168). Still any conformant vendor can optionally add support for additional file systems as is for example, the firmware in Apple Macs which supports the HFS+ file system.
 Try to compensate your memory for RAM intensive tasks. If you know you do a lot of memory intensive tasks which require more RAM than you have installed then raise this. You may also lower this or not use any swap at all if you have a lot of RAM. Remember that Arch based Linux distros like Obarun need a swap for hibernation though.
 When sizing the root partition with a separate home partition think about future system upgrades, huge applications and other things you might install on the road. Don't be too shabby here.
 Technically that is not correct. By specification the UEFI will search anywhere inside of the EFI system partition for an EFI application called BOOTX64.EFI for 64-bit systems and BOOTIA32.EFI for 32-bit systems. GRUB can even be instructed to install this way which would make NVRAM entries unnecessary.
 That does not mean you can not boot UEFI/GPT with syslinux. However it still has some limitations as of 2019 and requires some expertise which would imply more overall instructions to this manual. Refer to the Arch Wiki for details. https://wiki.archlinux.org/index.php/syslinux#UEFI_Systems