Re: cannot anymore boot into ubuntu

[Chris Murphy]

On Oct 13, 2012, at 3:36 AM, Averlon wrote:
> 
> grub-setup /dev/sdb

This isn't the correct command. It should be grub-install. 

And also since sdb is GPT without a BIOS Boot partition, you will either need 
to make 1MB of free space on sdb, and then add a BIOS Boot partition; or you 
will need to install grub onto sda - which of course will step on the Windows 
bootloader on sda.

Chances are you can get core.img stuffed into a BIOS Boot that's actually quite 
a bit smaller than 1MB if you don't have even 1MB free. If you have much less 
than 256KB free, then I would consider shrinking the ext4 partition sdb2, and 
inserting BIOS Boot between sda2 and sda3.

In any case, once sdb has a BIOS Boot partition, grub-install will find it 
automatically and use it.

Chris Murphy