how would I convert a BIOS system to UEFI

l0vot · 2014-01-20 17:25:16

All of my arch installs are set up as BIOS installs. A computer I own does not appear to support BIOS boot very well, so I cannot boot any BIOS installs on it. I would like to avoid doing a clean install, so I was wondering exactly how I would convert a BIOS install to a UEFI install. All of my installs are on a GPT disk and use GRUB as my boot-loader.

the_shiver · 2014-01-20 17:33:11

have a read at http://www.rodsbooks.com/bios2uefi/index.html written by forum fellow srs5694, also https://wiki.archlinux.org/index.php/Gr … _systems_2

in your specific case it'd prolly amount to simply creating an esp and (re)installing grub to it and setting your firmware/bios to boot in uefi mode

WonderWoofy · 2014-01-20 17:47:51

https://wiki.archlinux.org/index.php/UEFI

I think the biggest issue is that you are going to have to make an EFI System Partition. So that is going to involve resizing one of your partitions to allow some space. Fortunately, the ESP can reside anywhere on the disk, it doesn't have to be anywhere in particular. Legacy BIOS and UEFI can coexist on the same disk without any conflicts whatsoever. So you should be able to set up the ESP while the disk is booted from another computer if that is necessary.

Still, it would have been better if you had at least done a little research into this before posting here. At the very least, checking out wiki to see what it has to say about things should be an automatic first step.

l0vot · 2014-01-20 17:58:22

WonderWoofy wrote:

https://wiki.archlinux.org/index.php/UEFI
I think the biggest issue is that you are going to have to make an EFI System Partition. So that is going to involve resizing one of your partitions to allow some space. Fortunately, the ESP can reside anywhere on the disk, it doesn't have to be anywhere in particular. Legacy BIOS and UEFI can coexist on the same disk without any conflicts whatsoever. So you should be able to set up the ESP while the disk is booted from another computer if that is necessary.
Still, it would have been better if you had at least done a little research into this before posting here. At the very least, checking out wiki to see what it has to say about things should be an automatic first step.

I already checked the wiki, and I know i need an ESP, but I do not know the other steps required to get everything else to actually boot up with UEFI. I have some trouble working with things like this for the first time. Partition resizing is easy , and risk free for me due to my backup systems.

alroar · 2014-01-20 19:13:34

Switching to EFI Boot worked pretty flawless, gummiboot seems more logical to use for me than grub.

Have a read over here: https://wiki.archlinux.org/index.php/Gummiboot

Last edited by alroar (2014-01-20 19:13:56)

l0vot · 2014-01-20 19:55:50

So, I created an ESP and followed the instructions to install GRUB on it, but EFI boot fails on two different EFI-capable machines, I don't even get into GRUB. The device is recognized, but GRUB is not activated, I think I am missing something.

l0vot · 2014-01-30 01:32:06

I figured it out, I had to move $esp/EFI/grub/grubx64.efi to $esp/EFI/Boot/BOOTx64.efi for the laptop to recognize GRUB

fantab · 2014-01-30 13:20:13

WonderWoofy wrote:

https://wiki.archlinux.org/index.php/UEFI
I think the biggest issue is that you are going to have to make an EFI System Partition. So that is going to involve resizing one of your partitions to allow some space. Fortunately, the ESP can reside anywhere on the disk, it doesn't have to be anywhere in particular. Legacy BIOS and UEFI can coexist on the same disk without any conflicts whatsoever. So you should be able to set up the ESP while the disk is booted from another computer if that is necessary.
Still, it would have been better if you had at least done a little research into this before posting here. At the very least, checking out wiki to see what it has to say about things should be an automatic first step.

In my experience, ESP MUST reside within the first 100Gb of the HDD. Otherwise there will be boot problems.

My two cents...

mrunion · 2014-01-30 13:54:03

@fantab. I may be wrong, but I have 2 ESP partitions and I believe the second one is 300-400GB "in" the drive. I'm not at the laptop right now, but you have me curious. FWIW, I boot from the second ESP.

WonderWoofy · 2014-01-30 18:03:55

I've played a decent amount with UEFI and different disks and setups on my two UEFI machines. I have had ESPs at the beginning, the end, in the middle, on a different disk that one one booting and they all work just fine. I have also had more than one. I've even forgotten to mark the GUID as the ESP (code ef00 in gdisk), which still booted if I selected the disk as the boot device. I think in that case it looks for the first readable partition and then looks for /EFI/boot/bootx64.efi, so maybe if you are in that situation and have more than one vfat partition, it may cause issues.

Still, I'm not going to say that you are wrong fantab, as UEFI and the vendor shitfirmware on top of it can certainly have its bugs. Often times these bugs lead to a situation in which the full UEFI specifications are no longer followed. But you should be able to put the ESP anywhere on the disk that you want.

fantab · 2014-01-31 07:03:25

Yes, different OEMs have implemented the UEFI differently. The standard is not being adhered to by the OEM's. There are quite a few buggy UEFIs out there.
I help my friends and aquaintances to install Linux on their UEFI machines and I've had my share of bad experience with ESP way down on the HDD. So I just made it a rule (for myself) to setup ESP upfront and I feel its a good idea to have the boot files upfront on the HDD. I agree that in an ideal situation it shouldn't matter where the ESP is located on the HDD. UEFI should find the 'boot' flag.

ANOKNUSA · 2014-01-31 15:47:48

WonderWoofy wrote:

But you should be able to put the ESP anywhere on the disk that you want.

fantab wrote:

So I just made it a rule (for myself) to setup ESP upfront and I feel its a good idea to have the boot files upfront on the HDD.

When I made the switch, I backed up my system, repartitioned the drive, and restored the backup. It's just simpler that way, considering that a mistake in partitioning means restoring a backup anyway.

OT: I tend to partition all drives on all systems the way fantab suggests: Partitions are placed in the logical order in which the system needs them, both because a) on a spinning disk, the earlier partitions perform better; and b) because it's easier for me to prioritize partitions and grant them the space they "deserve." The ESP becomes /boot, and gets the bare minimum 512Mb (I only have Arch on my production machine); the /root system partition gets the next 5-8 Gb; /home gets the rest. The other advantage is that, should something go wrong with the boot process, or a partition need to be manipulated via dd or some other potentially risking procedure, one needn't interpret a partition table in which the order of partitions doesn't match the assigned drive numbers.

tl;dr: When mucking around with altering partition tables and filesystems, it's sometimes better to just back up and repartition the disk(s) in a logical way. That way, cryptic partition tables don't get tossed into the stack of technical documents you need to cross-reference to complete the process.

gegenschall · 2014-02-01 03:03:35

I did this a while ago and it is not that hard. I basically did the following steps but it somehow depends on your partition layout. For me that was: / /boot and /home as seperate partitions.You might need to adjust accordingly.
These steps (esp. 3.) will only work if you already booted using EFI. If you did not: Boot a live CD using UEFI(!) and chroot into your arch install.

If you haven't done that, some systems require the partition scheme to be GPT. You can transform from MBR with gdisk (roughly: gdisk /dev/sdX, r, f. But PLEASE, read the manuals...)
Copy your /boot over to some other directory, i.e. back-it-up. Remove your /boot (ext3/4) partition and create a new one in its place but this time as partition type EF00 and FAT32 as its filesystem. Should be at least 100MB in size, mine is 512MB and the first partition. This step assumes you do not store anything else in /boot and don't want to use GRUB (which I suggest).
Install gummiboot and configure it. It's awesome. For details see the wiki. In most cases installation should work out fine, and the system should just load gummiboot. If it does not, you'll need to fiddle around with efibootmgr.
Either, copy over your kernel and initramfs from the /boot-Backup or have pacman reinstall the kernel for you
Have a rescue disk at hand in case something goes wrong

Have fun!

Arch Linux

#1 2014-01-20 17:25:16

how would I convert a BIOS system to UEFI

#2 2014-01-20 17:33:11

Re: how would I convert a BIOS system to UEFI

#3 2014-01-20 17:47:51

Re: how would I convert a BIOS system to UEFI

#4 2014-01-20 17:58:22

Re: how would I convert a BIOS system to UEFI

#5 2014-01-20 19:13:34

Re: how would I convert a BIOS system to UEFI

#6 2014-01-20 19:55:50

Re: how would I convert a BIOS system to UEFI

#7 2014-01-30 01:32:06

Re: how would I convert a BIOS system to UEFI

#8 2014-01-30 13:20:13

Re: how would I convert a BIOS system to UEFI

#9 2014-01-30 13:54:03

Re: how would I convert a BIOS system to UEFI

#10 2014-01-30 18:03:55

Re: how would I convert a BIOS system to UEFI

#11 2014-01-31 07:03:25

Re: how would I convert a BIOS system to UEFI

#12 2014-01-31 15:47:48

Re: how would I convert a BIOS system to UEFI

#13 2014-02-01 03:03:35

Re: how would I convert a BIOS system to UEFI

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