Multiboot VBE info with grub efi

[zartech222]

Hello,

I'm currently trying to boot my multiboot compliant kernel, which works well with grub for bios, with grub efi. But it get stuck after the 'boot' command.
I think that the problem comes from the video mode information provided by grub.

I have searched on Google but I found nothing. That's why I'm asking you.

What is the difference between grub bios and grub efi for a multiboot compliant kernel boot?

[rdos]

Hello,

I'm currently trying to boot my multiboot compliant kernel, which works well with grub for bios, with grub efi. But it get stuck after the 'boot' command.
I think that the problem comes from the video mode information provided by grub.

I have searched on Google but I found nothing. That's why I'm asking you.

What is the difference between grub bios and grub efi for a multiboot compliant kernel boot?

VBE no longer is (or needs to be) supported by EFI. In EFI, you setup a video mode before exiting boot-services, and then normally won't change it (unless you have a native video driver). It means that video handling will differ between BIOS and EFI boots.

[zartech222]

How could it be possible to detect and tohandle this video mode, if it is possible, after grub boot the kernel?

[rdos]

How could it be possible to detect and tohandle this video mode, if it is possible, after grub boot the kernel?

I think it is better if you adapt more directly to EFI rather than relying on GRUB for it. I have separate boot-loaders for EFI, BIOS and multiboot (GRUB). You really need to have that if you want to support a wide range of systems and configurations. It's a tough challenge to both support booting in a text-mode and the EFI LFB-based mode, especially if you have fatal boot handlers that outputs text, but it's possible to do. Of course, if you switch to a fixed graphics mode early in the boot-process, it becomes easier to handle.