Gentoo Archives: gentoo-user

From: Facundo Curti <facu.curti@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] Re: Change EFI to BIOS Boot
Date: Sat, 19 Apr 2014 17:06:16
Message-Id: CABxff5-f4T=qKkhF16o+mgSdj4vEN-1kEwn16STYjvbcwUQYyQ@mail.gmail.com
In Reply to: Re: [gentoo-user] Re: Change EFI to BIOS Boot by Tom H
1 2014-04-19 12:34 GMT-03:00 Tom H <tomh0665@×××××.com>:
2 > On Sun, Apr 13, 2014 at 11:08 AM, Jonathan Callen <jcallen@g.o> wrote:
3 >> On 04/12/2014 08:19 AM, Tom H wrote:
4 >>>
5 >>> You can have a gpt partition table with BIOS but if you want to boot from that disk, you need a
6 >>> bios_boot partition (which the OP has) for grub to embed a binary.
7 >>
8 >> Technically, I don't think you need a bios_boot partition if you leave enough space between the
9 >> partition table and the first partition (I don't recall having a problem when my first partition
10 >> started 2048 sectors (1MiB) into the disk).
11 >
12 > You're correct if you're talking about an msdos-labelled disk with
13 > bios firmware because having the first partition start on 2048 as it
14 > does now rather on 63 as it used to because the post-mbr gap will
15 > always be big enough for grub to embed core.img.
16 >
17 > But on a gpt-labelled disk with bios firmware, there's a <something>
18 > mbr into which grub embeds boot.img but there's no post-mbr gap. So a
19 > bios_boot partition's needed in order to embed core.img (IIRC parted
20 > calls it grub_bios or bios_grub).
21 >
22
23 As I could not fix it, I solved it making backup, formating with
24 ms_dos table, and restoring backup. :P