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chaseis4344
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Joined: 12 Sep 2024
Posts: 1

PostPosted: Thu Sep 12, 2024 2:14 pm    Post subject: GRUB refuses to stop generating EFI entries Reply with quote

Hey,
I have installed Gentoo successfully with 1 small hiccup.

GRUB refuses to generate a /boot/grub/grub.cfg that uses MBR.

This issues causes my system to boot into the grub screen every boot.
This all happened because I was making my system UEFI based on the idea that the older system I was working on probably had the right firmware for UEFI mode.
I was wrong.

Now since I followed the handbook and enabled the UEFI flag for grub in the configs grub-mkconfig refuses to generate a non-UEFI boot.
I can get it to boot by specifying where vmlinuz and initramfs are, but it has never booted like it has when I installed arch

sorry if this post is uninformed, I am entirely new to gentoo
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sabayonino
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Joined: 03 Jan 2012
Posts: 1036

PostPosted: Thu Sep 12, 2024 3:38 pm    Post subject: Reply with quote

Hi.
BIOS boot works only with DOS disc table not GPT table

or you need the hybrid boot MBR+UEFI .
you need a small partition marked as bios_boot to install grub for MBR boot on GPT table disk

Hybrid MBR+UEFI boot disk partition schema
Code:

Disk /dev/sde: 223,57 GiB, 240057409536 bytes, 468862128 sectors
Disk model: Name
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 700981BF-1069-491E-B47C-B3CA35C35A5C

/dev/sde1     2048      4095      2048     1M BIOS boot
/dev/sde2     4096    208895    204800   100M EFI System
/dev/sde3   208896 468860927 468652032 223,5G Linux filesystem

_________________
LRS i586 on G.Drive
LRS x86-64 EFI on MEGA


Last edited by sabayonino on Thu Sep 12, 2024 3:46 pm; edited 2 times in total
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sMueggli
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Joined: 03 Sep 2022
Posts: 489

PostPosted: Thu Sep 12, 2024 3:41 pm    Post subject: Re: GRUB refuses to stop generating EFI entries Reply with quote

chaseis4344 wrote:
GRUB refuses to generate a /boot/grub/grub.cfg that uses MBR.


Not sure, what you mean. Based on the partition table, Grub is loading the specific module. If the partition table is MBR than it will load the module for MBR. If the partition table is GPT it will load the module for GPT. But this depends on the partition table and not the boot mode.

Probably you mean the boot mode? That you want to boot in BIOS Legacy mode instead of UEFI?

chaseis4344 wrote:

This issues causes my system to boot into the grub screen every boot.
This all happened because I was making my system UEFI based on the idea that the older system I was working on probably had the right firmware for UEFI mode.
I was wrong.

Now since I followed the handbook and enabled the UEFI flag for grub in the configs grub-mkconfig refuses to generate a non-UEFI boot.
I can get it to boot by specifying where vmlinuz and initramfs are, but it has never booted like it has when I installed arch


Please show the complete /boot/grub/grub.cfg and post the output of

Code:
efibootmgr
grep GRUB /etc/portage/make.conf
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sMueggli
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Joined: 03 Sep 2022
Posts: 489

PostPosted: Thu Sep 12, 2024 3:47 pm    Post subject: Reply with quote

sabayonino wrote:
Hi.
BIOS boot works only with DOS disc table not GPT table

or you need the hybrid boot GPT+UEFI .
you need a small partition marked as bios_boot to install grub for DOS boot


That's wrong/mixed.

  • BIOS Legacy mode
    • MBR: no special setting needed
    • GPT: a bios_grub partition is needed to be able to install Grub

  • UEFI mode
    • MBR: The ESP should be a primary partition
    • GPT: no special setting needed

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alamahant
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Joined: 23 Mar 2019
Posts: 3916

PostPosted: Thu Sep 12, 2024 7:45 pm    Post subject: Reply with quote

Just comment out
Code:

#GRUB_PLATFORMS="efi-64"

in make.conf
then
Code:

emerge -1av grub
grub-install /dev/sdx

If your disk is gpt then create an 1M partition with
Code:

Select partition type BIOS boot for fdisk.
Select partition type code ef02 for gdisk.
For parted set/activate the flag bios_grub on the partition.

flag set.
BEFORE reinstalling grub.
Plz post
Code:

lsblk

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