Arch Linux

M5Hc6UsQ

Member

Registered: 2018-02-26

Posts: 33

[Solved] Multiboot USB drive with hybrid MBR

I want to setup an bootable USB drive which can be used both on BIOS and UEFI PCs. I followed the guide from the wiki [1], but had no success. I've tested this on three different PCs. A 1 year old PCs, a few years old Laptop and a true legacy system which only supports BIOS. None of them were able to load Grub in BIOS mode. In UEFI mode in works just fine, except for the legacy system of course.

Does someone actually tried this setup and got it working? I feel kinda stupid, because this guide can be found all over the internet.

[1] https://wiki.archlinux.org/index.php/Mu … T/MBR_boot

Last edited by M5Hc6UsQ (2020-06-10 08:19:10)

mxfm

Member

Registered: 2015-10-23

Posts: 166

Re: [Solved] Multiboot USB drive with hybrid MBR

I didn't use such setup, but legacy BIOS may reject booting from modern disks which have native 4K sectors (I have such disk which is not bootable on one of my old laptops).

You can test whether hybrid setup is correct in following way. Wipe the MBR partition table (of course, if is 'slave' to GPT partition table, otherwise you will delete all partitions) and install grub-i386 (with special small partition called bios-grub) on disk, which corresponds to legacy BIOS regime. In computer BIOS settings set legacy regime (if there is such option). If you can boot i386-grub, then something is wrong with hybrid MBR setup. Otherwise, booting of that particular drive on that machine is not supported.

M5Hc6UsQ

Member

Registered: 2018-02-26

Posts: 33

Re: [Solved] Multiboot USB drive with hybrid MBR

Figured it out. There is an error in the guide. The bootable flag must be on the first partition not the third.

mxfm

Member

Registered: 2015-10-23

Posts: 166

Re: [Solved] Multiboot USB drive with hybrid MBR

Figured it out. There is an error in the guide. The bootable flag must be on the first partition not the third.

Perhaps you can update the wiki?