I'm new to Linux and need help for installing ubuntu on my computer.

  • I currently have windows10 installed on a 232 Gb ssd.
  • I have a secondary 2.3 Tb hdd which uses gpt.
  • Windows boots in Legacy BIOS mode, so not with UEFI.

I want to install ubuntu on a partition of the secondary hdd.

I already tried and partitioned my hdd, allocating something like 500Gb to install ubuntu. I created a swap partition of 12 Gb and the rest of the 500 Gb for an ext4 partition. The installation went well and after that I went to my BIOS to choose to boot from my hdd. But that just lead me to a blinking underscore. I also tried to create a 1 Mb BIOS-boot partition but that changed nothing.

Any suggestions on what I'm doing wrong?

  • 2
    You need the 1MB unformatted bios_grub partition on the gpt drive, if installing grub to the protective MBR of the gpt drive (which you should). Grub will offer to boot both Windows & Ubuntu if Windows fast start up is off. And if grub does not boot Windows you can directly boot SSD and Windows boot loader. Be sure to install grub to sdb. If this does not reinstall grub to MBR of sdb correctly, try full uninstall/reinstall of grub. If not post link to summary report it makes. help.ubuntu.com/community/Boot-Repair do not run auto fix as that will install grub to all MBRs.
    – oldfred
    Apr 1, 2017 at 16:48

1 Answer 1


I finally found the problem of my setup and succeed to install a dual boot.

The bios_grub partition needed to be at the beginning of the gpt hdd (100 Gb max from the start of the disk). As I was installing ubuntu in a partition of 500 Gb located at the end of my 2.5 Tb hdd, nothing was found to be booted.


  • Note that the BIOS Boot Partition (identified in GRUB by a bios_grub flag) is normally sized at 1 MiB. You specify it as "<100 Gb", but 100 GiB (or GB or even Gb; see here for more on these values) is way oversized for the BIOS Boot Partition.
    – Rod Smith
    Apr 3, 2017 at 13:42
  • Sorry I wasn't clear in my response. I meant it needed to be located at 100Gb maximum from the start of the disk. I stayed with a 1Mb partition for the BIOS Boot Partition. Apr 4, 2017 at 7:47
  • The BIOS Boot Partition can go anywhere on the disk that the BIOS can read. On relatively modern systems, this can be up to 2TiB. A placement at a maximum of 100 GB (I assume that's what you mean; 1B = 8b) would be extremely unusual.
    – Rod Smith
    Apr 4, 2017 at 18:34
  • Yes sorry I was mixing up Gb and GB but I was effectively speaking about GB. I know it has surprised me too and maybe I'm misinterpreting what really worked. Do you have any clue on what else could have solved my problems? Note that I also moved my ubuntu partition to the beginning of the disk. Apr 12, 2017 at 8:45

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .