How can I know which partition is EFI system partition?

linux partitioning mount arch-linux efi

12,016

None of them. Either you don't have an EFI system, or Windows wasn't installed in EFI mode.

If you had an EFI system partition, it would always have the ef type code instead of the usual 07 or 82, and lsblk -f would show it as having a "vfat" filesystem.

Also, since Windows is rather picky about it, the disk would have a GPT disklabel (yours shows "dos" which means MBR), and fdisk wouldn't even show the type ids.

That first 100 MB partition is a "Microsoft System Reserved Partition"; while similar in purpose (even meant to mirror EFI layout), it is completely specific to the Windows boot process.

12,016

pushandpop

T-1000 is my worsest nightmare.

Updated on September 18, 2022

Comments

pushandpop over 1 year

I want to install ArchLinux from working dual-boot system. There's one step where I got stuck:

# Mount the EFI System partition with: sh-4.3# mount /dev/sdaX /mnt/boot/efi

I ran fdisk -l command and got its output. How can I know which of this partitions is exactly the EFI one? Is it the one with only 100mb storage?
pushandpop about 9 years

Hm, I have an UEFI-motherboard and thought this means that I have an EFI partition. I'm not strong in this stuff, really. Should I just create this partition or it's okay to continue without mounting EFI partition?
Rod Smith about 9 years

Most EFIs provide a feature called the Compatibility Support Module (CSM), which enables the EFI to use BIOS-mode boot loaders and boot BIOS-mode OSes. Your system appears to be using this feature to boot Windows in BIOS mode. In some sense, you can think of your computer as having a BIOS, not an EFI; however, there is a danger: If you mistakenly install Linux in EFI mode, you'll have a mixed-mode installation, which will be difficult to dual-boot. Thus, you should be careful to install Linux in BIOS/CSM/legacy mode.
pushandpop about 9 years

@RodSmith, wow, you put everything in its place in my mind, thank you. I'm gonna find another way and this question, as I think, can be closed. Thanks, again!
Rod Smith about 9 years

Follow the Arch Linux instructions for installing in BIOS mode and you should be OK.