This is a three step procedure:
- Use
gdiskto convert the partition type from MBR to GPT (without data loss). - Use
gdiskto add a new BIOS boot partition (EF02type). - Use
grub-installto install the boot loader into the new BIOS boot partition.
Before starting, make sure you have a backup, and make sure to have a linux live boot ready to rescue your system. It's easy to mess this up!
gdisk /dev/sda
nto create a new partition. Needs to be about 1MB. You can probably squeeze this in from sectors 34-2047. UseLorlto look up the code for "BIOS boot" (ef02).
w
partprobe /dev/sda