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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?

zartech222 wrote: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.

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

zartech222 wrote: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.