why is it that my bios can't see a gpt hdd?

Discussion in 'BIOS Mods' started by Pockets69, Jul 24, 2014.

  1. Pockets69

    Pockets69 MDL Novice

    Feb 24, 2014
    #1 Pockets69, Jul 24, 2014
    Last edited: Jul 24, 2014
    Hello guys

    I got a rather simple question at first, but need confirmation why it happens, as I have been doing my fair search on google but it only shows people wanting to downgrade windows 8 to windows 7 -.-'

    Anyway the following is happening, i have 3 pcs here that i am working on, one being a desktop the other 2 being laptops, all of them have formatted hard drives, (2tb HDD for the desktop, 1TB sshd for the laptops) the hard drives are gpt and formatted as fat32, now the problem is, my desktop computer (which has an ami aptio uefi bios) can see the hard drive in legacy mode you can select it as a boot volume, obviously nothing happens since there is nothing there, but it can see the hdd, as for the other two laptops (they are both asus, one s46 the other s200ca) and the bios again are ami aptio uefi bioses on both, yet the laptops they can't see the hard drive on legacy, I can't select it as a boot volume.

    why does this happen? is it because of the bios? or is it something else entirely? does anyone have any clue on what to do to allow the laptops to see the gpt disks?

    thank you all in advance.

    EDIT since this has already more than 100 views and no replies, here is a too long didn't read, also i ll post pictures if needed.

    TL;DR: 3 different hdds formated as gpt 3 different computers UEFI bios in legacy mode recognizes one hdd, but not the others.
  2. Pockets69

    Pockets69 MDL Novice

    Feb 24, 2014
    Ok after further investigation I have narrowed it down to the following option that is enabled when legacy mode is enabled on uefi bios, the option is called:

    Hard Drive BBS Priorities.

    Now again the strange thing is, the disk on the desktop is selectable on the hard drive bbs priorities, but on the laptops, the hard drive bbs priorities on one it only sees the ssd (which is a small caching ssd, formatted as fat32 with mbr partition) and on the other laptop it doesn't see anything since there is no caching ssd.

    so the problem stands but it has been potentially narrowed down to the hard drive bbs priorities

    again why does the hard drive bbs priorities on the desktop can see the gpt hdd, and it is selectable, and why is it that on the other two laptops it can't see the gpt disk?

    can the bios be modded to allow for it to be seen?

    please help me out guys
  3. Flipp3r

    Flipp3r MDL Expert

    Feb 11, 2009
    What OS did the notebooks ship with? Even though they are modern UEFI, if they shipped with Windows 7 then they are probably setup for LEGACY.
    I know for some MSI models they actually have a separate UEFI to download for Legacy Win7 & UEFI Win8...

    When you say fat32 are you talking about the system partition? The main visible partition should be ntfs...
  4. Pockets69

    Pockets69 MDL Novice

    Feb 24, 2014
    Hey Flipp3r thank you for the reply.

    The OS shipped with the HDD has nothing to do with it, the problem is the partition scheme, yes they are setup for legacy right now, because i want them in legacy, but i want them to recognize the gpt disk that is installed, on the desktop computer (its a gigabyte board z77n-Wifi) it recognizes it perfectly on legacy.

    the same disk on my other two laptops (an asus s200 and asus s46) the VERY same disk is not recognized.

    No the formatting does not matter at all, it would be recognized if i format it as ext4 (linux filesystem), i just want it to detect the drive, the formatting has nothing to do with that, the partition scheme does (gpt or MBR), in this case the GPT disk.

    now the funny thing is, i decided to connect the same disk that does not get recognized when connected internally (sata) on my lptop, i decided to connect it to the USB port with a SATAtoUSB adapter, guess what? the same gpt disk that is not recognized internally, it is recognized on the usb.

    this is ridiculous, the Hard Drive BBS priorities doesn't list a gpt disk connected to the internal sata port, but recognizes it when connected to usb.