Why do I need these? I have installed Ubuntu under a non UEFI (master boot record) and have installed Ubuntu with no 'biosgrub' and it works fine, whereas other times I am asked to make a 'biosgrub' partition. I have no idea why sometimes I need it and others I don't (these have both been on the same system).
And the same thing happens when I use UEFI (GUID Partition Table). The only difference is I am asked to make a 'EFI boot partition', but as with the 'biosgrub', sometimes I am asked to make it and sometimes I am not asked to make it.
For my current install I was asked to make one but I didn't and my system is fine. There is no change in the system, same hardware, BIOS etc… Could anyone shed light on this?