Re: Chainload grub to grub?

[Goh Lip]

On 3/6/23 17:11, Michael Peters wrote:
> Hi. I'm trying to figure out how to chainload one grub to another.
>
> bios boot, not UEFI.
> grub 2.06 built from source.
.
.
.
.
> Is chainloading grub from one physical drive to grub on another physical
> drive possible?
>
> How is it done?


Yes, try multiboot commands to core.img in menuentries of this sort...

menuentry "Other OS 1"  {
               search --no-floppy --fs-uuid --set=xxxxxxxxxxxxxxxxx
               multiboot /boot/grub/i386-pc/core.img
     }




> That attempt based on Windows 7 example I saw.

Use ntldr command for windows.

menuentry  "Windows" {
  insmod part_msdos
  insmod ntfs
  search --no-floppy --fs-uuid --set=xxxxxxxxxxxxxxx
  ntldr /bootmgr
}


*But* I think the problem is the OS you are trying to boot up is in a 
GPT disk, not a msdos disk
as shown by your entries you gave using PARTUUID which can only apply to 
GPT disks.

> # filesystem root=/dev/sda2
> menuentry "GNU/Linux, Linux 6.1.15-lfs-11.3" {
>    linux /vmlinuz-6.1.15-lfs-11.3 root=PARTUUID=d92d2b64-02 ro
> }
> menuentry "GNU/Linux, Linux 6.1.14-lfs-11.3" {
>    linux /vmlinuz-6.1.14-lfs-11.3 root=PARTUUID=d92d2b64-02 ro
> }

Unless you have set up your GPT disk to have a *flagged* BIOS Boot 
partition, booting in bios-legacy will be a problem.