[SOLVED] UEFI usb bootable on different machines

mxfm · 2015-10-25 09:27:57

Hello, community.

For a long time I was using linux on external usb disk formatted as old MBR (+ windows on internal drive). Recently I changed the disk to GPT and installed grub-efi (I am new to it). My expectation was that as in the past I can plug the disk and boot from it on ny machine.

The problem is that some BIOS firmware do not scan all drives for UEFI boot loaders as it was in legacy boot mode. AFAIK BIOS reads ACPI NVS for loader link and loads it from internal drive (or external, if the system was installed on local machine). So, this breaks the way I used disk in the past - just plug the disk on any machine and boot from it. Now, in order to boot from disk one need to install loader through efibootmgr, disable automatic removal from windows on each machine (which is impossible without prior installation). Luckily, on one machine I have Insyde BIOS and can choose boot from EFI file option and another machine BIOS scans for ESP partions on all drives. Unfortuantely, other machines don't have such option - consequently, it is impossible to boot the usb disk. And switching to legacy boot mode is not helpful because UEFI loader is not supported. My current solution is to have MBR grub bootable flash drive where I can point to use linux and initrd from usb disk.

So, the question is - is there any way to to boot UEFI external disk without prior installation and without additional MBR bootable disk for machines which do not scan all disks for loaders?

Last edited by mxfm (2015-10-28 10:28:12)

Head_on_a_Stick · 2015-10-25 16:48:42

If you're using GRUB, try coping /boot/efi/EFI/grub/grubx64.efi to /boot/efi/EFI/boot/bootx64.efi
https://wiki.archlinux.org/index.php/GRUB#EFI_path

It may be worth also copying the GRUB .efi loader to /boot/efi/Microsoft/Boot/bootmgfw.efi (if you mount /boot to the EFI system partition) as this can "trick" motherboards pre-programmed to boot Windows .efi loaders automatically.

Last edited by Head_on_a_Stick (2015-10-25 16:49:31)

mxfm · 2015-10-26 07:04:40

Well, this helped a lot! I tested on several machines, it worked. Assume others will also be OK.

The thread can be marked as solved.

Head_on_a_Stick · 2015-10-28 08:33:10

Good stuff

mxfm wrote:

The thread can be marked as solved.

Please edit the title & add [SOLVED] to the start.

Arch Linux

#1 2015-10-25 09:27:57

[SOLVED] UEFI usb bootable on different machines

#2 2015-10-25 16:48:42

Re: [SOLVED] UEFI usb bootable on different machines

#3 2015-10-26 07:04:40

Re: [SOLVED] UEFI usb bootable on different machines

#4 2015-10-28 08:33:10

Re: [SOLVED] UEFI usb bootable on different machines

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