Hi nathan,

GRUB's configuration [1] options do not document any option enabling 
screen rotation
 > But despite what fbcon options I use, grub is still rotated to the 
right. I've tried with video=efifb fbcon=rotate:1 and fbcon=rotate_all:1 
as well as a few other options under GRUB_CMDLINE_LINUX_DEFAULT. 
GRUB_CMDLINE_LINUX options have worked for the CLI itself but not GRUB's 
GUI.

 From what I understand all these fbcon [2] options apply to the kernel.

GRUB is a bootloader, it starts the kernel, and it does not run linux, 
so any kernel (aka linux) specific options do not apply to it.

Similarly the GRUB_CMDLINE_LINUX's purpose is to send arguments to the 
kernel when GRUB starts it. Therefore it is normal that GRUB does not 
interpret these options for itself.

If you just do not want to see a "badly rotated" bootloader, then you 
can probably mask the issue, by hiding GRUB, or using any other 
bootloader that by default will boot a predefined kernel without showing 
on screen.

((Or you can always try patching GRUB's video driver to do the pixel 
translation if you are desperate for a correctly rotated bootloader ;-) ))

It seems normal to me that this feature should not be available, as from 
what I understand a bootloader's purpose is to start the linux kernel, 
initramfs as simply as possible, without complicated graphics drivers... 
So adding a pixel translation engine for rotations seems a little bit 
out of scope.

Concerning rEFInd, I found the reddit subchannel in which they claim it 
is possible. But I doubt it is true, I understand that it depends on the 
same UEFI graphics output protocol [3] as GRUB. So I don't see how it 
could work, except if the firmware were to expose such an option (in the 
Unified Extensible Firmware Interface (UEFI)), but once again this is 
independent of the bootloader in use.

Don't hesitate to check the arch wiki for more details on the boot 
process [4].

I am definitely not an expert on the subject so feel free to contradict 
me if I said anything wrong.

Cheers,

toby

[1] 
https://www.gnu.org/software/grub/manual/grub/grub.html#Simple-configuration
[2] https://docs.kernel.org/fb/fbcon.html
[3] https://wiki.osdev.org/GOP
[4] https://wiki.archlinux.org/title/Arch_boot_process

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