REFIT boot problem, GRUB not detected

Hello Shanker,

If i were you, i would create a BIOS_boot partition (>1Mo, unformatted filesystem, bios_grub flag), then click "Recommended repair". (and indicate the new URL that will appear please)
However, if your boot was previously ok without any BIOS_boot partition, and because efi is not mentionned in your fstab, i guess there was a trick with Refit chainloading GRUB, but i don't know Refit enough to say.

Hello YannUbuntu,

Does it make a difference where the BIOS_boot partition is created? I am tempted to create it at the end of the disk (after the ubuntu partition). The reason is that I would want all the bootloaders (Mac bootloader, EFI, Ubuntu) to know where the existing OS's are. Does that sound like a good idea to you?

Thanks,
btw. Congratulations on an excellently written and very useful program!

Thanks.
The BIOS_boot partition does not need to be at the very beginning of the disk, so it's worth have a try at the end.
If not good, then try to reduce your SWAP in order to create a BIOS_boot partition before the Ubuntu partition.

Hi YannUbuntu,

I made a bios partition at the end of the disk and then reran boot repair. The good news is that using the super GRUB2 disk, now I can easily load ubuntu (previously I could only load it in low-graphics single session mode). However, using normal boot (selection from REFIT screen), upon choosing ubuntu I get the error "No bootable device -- insert boot disk and press any key". The output from boot repair is here: http://paste.ubuntu.com/981223/.

And although you notice that grub2 is installed in the mbr, It is also installed in the ubuntu partition. Isn't boot repair supposed to purge all previous installations of grub and then install it on the mbr?

Is there anything else wrong?

Cheers
Shanker

i summarize (for me , and for anybody reading this who may have better idea than me):
- GPT disk
- in your 1st post:"(Back then, boot repair gave me an option of installing on MBR or on partition 4/ubuntu. MBR would work, and partition 4 would not)" : Refit was chainloading to MBR, so no EFI was used (no efi in fstab, but a EFI partition maybe for MacOS), nor BIOS_boot partition.
- Problem appeared: no more core.img in Ubuntu's partition. Maybe due to a GRUB2 update (10.04.1 -> 10.04.4 ?). Reinstalling GRUB after creating BIOS_boot partition seemed ok (MBR was updated adn core.img was created in the BIOS_boot part), but Refit wasn't able to chainload.

Here is what i would try if i were you (but you may want to wait for other people advice):
1) backup data and content of the EFI partition (sda1)
2) use the "Restore MBR" option of Boot-Repair, then check Refit's message (=reboot and see if you still have the "No bootable device -- insert boot disk and press any key" message or not). This may give us a clue.
3) purge GRUB, then reinstall an older version of GRUB (eg http://packages.ubuntu.com/hardy/grub-pc ) in the MBR and in the bootsector of Ubuntu partition. Then check Refit's message.
4) purge GRUB, then reinstall a recent version of GRUB (via the option in Boot-Repair)in the MBR and in the bootsector of Ubuntu partition. Then check Refit's message.
5) Setup your BIOS to boot on your live-CD in EFI mode (if possible), then install grub-efi instead of grub-pc. Reboot. If still not good, you may need to make your BIOS boot on the /sda1/EFI/.../grub64*.efi file
6) Via gParted reduce 10.04 partition (leave 20Go free space). Burn a 12.04 live-CD, and install 12.04 in this free space.

Please indicate what you observe, indicate the URL that appears after each Boot-Repair use, and create a BootInfo URL before&after each of these 6 operations.