Booting from GPT

[enterzakari.xd]

I've been trying to install Win10 on a WD Black HDD from the USB setup media provided by MS.

My first issue was being unable to install windows on the formatted drive because it needed to be marked as GPT, which I eventually managed to sort. Now I have installed windows and I have the 4 partitions (sys info, efi, etc.etc.).

However, when I attempt to boot from the disk, I get the, "Reboot and select proper Boot Device", message. Upon further reading, I went through the process of installing Windows again, ensuring that my BIOS was in UEFI mode, but to the same effect.

Now, from all the rebooting, my PSU appears to have blown up; so I thought I'd use this time to get figure how I'm actually gonna get an OS on my HDD when I fix it!

TLDR: Win-setup enforces that it must be installed on a GPT drive, but BIOS (in UEFI mode) won't boot from said GPT disk.

Any suggestions appreciated!

 

[Colif]

what motherboard do you have?

win 10 will only format drives as GPT if the motherboard supports UEFI boot method. Your PC obviously does but something is wrong.

In boot order, is there a choice called Windows Boot Manager? If its a choice, it should be top of boot order

There are two boot methods in most new motherboards, Legacy & UEFI.
In a legacy system, it uses MBR drive format which will put the boot partition in the 1st partition of disk.
Legacy boot method only supports MBR, and will only look in 1st partition on 1st drive for boot instructions

In a UEFI system, the disk format is GPT and the boot partition can be anywhere, on any disk. Its location is stored in the windows boot manager
UEFI supports both MBR & GPT and knows better than to just look on 1st drive in PC.

My guess is that your BIOS is defaulting to Legacy but since drives are GPT, it isn't looking in the right place for the boot partition

windows should be able to fix it, without you setting anything in BIOS. It is able to set up the UEFI bios boot how it needs it. Its a feature of UEFI

If you had a PSU that worked now, i would suggest booting from the installer and run startup repair - it might fix it

change boot order so USB is first, hdd second
boot from installer
on screen after languages, choose repair this pc, not install.
choose troubleshoot
choose advanced
choose start up repair - this will scan PC and maybe fix this - will ask for logon info

other way to do it is shown here - https://www.lifewire.com/how-to-rebuild-the-bcd-in-windows-2624508

 

[enterzakari.xd]

what motherboard do you have?

win 10 will only format drives as GPT if the motherboard supports UEFI boot method. Your PC obviously does but something is wrong.

In boot order, is there a choice called Windows Boot Manager? If its a choice, it should be top of boot order

There are two boot methods in most new motherboards, Legacy & UEFI.
In a legacy system, it uses MBR drive format which will put the boot partition in the 1st partition of disk.
Legacy boot method only supports MBR, and will only look in 1st partition on 1st drive for boot instructions

In a UEFI system, the disk format is GPT and the boot partition can be anywhere, on any disk. Its location is stored in the windows boot manager
UEFI supports both MBR & GPT and knows better than to just look on 1st drive in PC.

My guess is that your BIOS is defaulting to Legacy but since drives are GPT, it isn't looking in the right place for the boot partition

windows should be able to fix it, without you setting anything in BIOS. It is able to set up the UEFI bios boot how it needs it. Its a feature of UEFI

If you had a PSU that worked now, i would suggest booting from the installer and run startup repair - it might fix it

change boot order so USB is first, hdd second
boot from installer
on screen after languages, choose repair this pc, not install.
choose troubleshoot
choose advanced
choose start up repair - this will scan PC and maybe fix this - will ask for logon info

other way to do it is shown here - https://www.lifewire.com/how-to-rebuild-the-bcd-in-windows-2624508

Thanks for your reply - apologies I didn't respond sooner, I've been waiting for an opportunity to try your suggestions out.

Firstly, my mobo is a Gigabyte 990fxa UD3.

Unfortunately, running startup repair only resulted in the installer starting again. I'm stumped because I've set my BIOS options to "UEFI only", which still fails to pick up hdd (I've even disconnected all other drives). Likewise, I've tried changing options to "Legacy only" but it seems that the hdd isn't even compatible with legacy booting (I can't install windows on it in legacy mode).

 

[Colif]

Do you know which revision motherboard you have? there are 4 versions - 1.0, 1.1, 3.0, & 4.0
what bios version are you on?
latest bios for versions are below
1.0 - F9
1.1 - F9
3.0 - FC
4.0 - F4
note. Just cause bios numbers are same, doesn't mean they same for each motherboard. F4 for 3.0 is not same date as F4 for Version 1.0, for example.

It appears some revisions of your motherboard use something called Hybrid EFI - https://forum.giga-byte.co.uk/index.php?topic=17750.0 - I cannot tell if all do, they all have Dualbios though. I didn't notice you had 4 different versions to choose from so the manula I linked above could be wrong one.

First things first: this is not an EFI BIOS (although, technically, EFI is more of a replacement for the BIOS than a specific kind of BIOS). Gigabyte's 6-series motherboards still use an old-school Award BIOS. However, they incorporate an EFI bootloader to enable support for hard drives larger than 2.2TB. You'll need a Gigabyte software utility to use the full capacity of those drives on older operating systems, but the app isn't required for Windows 7 x64, which is the OS we expect most folks to be running with 6-series motherboards.

Native support for 3TB hard drives is one of EFI's most important features, and this bootloader approach appears to deliver the goods without replacing the entire BIOS.

https://techreport.com/news/20941/is-it-efi-or-not-gigabyte-hybrid-efi-bios-explained

How big is the hdd? that reaction seems odd, even if drive is bigger than 2,2tb Legacy should still see the hdd, it just can't use all of it. You should be able to install in legacy mode if you set it as boot method. It will just need you to delete GPT partitions as it can only boot off MBR.

 

[enterzakari.xd]

Do you know which revision motherboard you have? there are 4 versions - 1.0, 1.1, 3.0, & 4.0
what bios version are you on?
latest bios for versions are below
1.0 - F9
1.1 - F9
3.0 - FC
4.0 - F4
note. Just cause bios numbers are same, doesn't mean they same for each motherboard. F4 for 3.0 is not same date as F4 for Version 1.0, for example.

It appears some revisions of your motherboard use something called Hybrid EFI - https://forum.giga-byte.co.uk/index.php?topic=17750.0 - I cannot tell if all do, they all have Dualbios though. I didn't notice you had 4 different versions to choose from so the manula I linked above could be wrong one.

First things first: this is not an EFI BIOS (although, technically, EFI is more of a replacement for the BIOS than a specific kind of BIOS). Gigabyte's 6-series motherboards still use an old-school Award BIOS. However, they incorporate an EFI bootloader to enable support for hard drives larger than 2.2TB. You'll need a Gigabyte software utility to use the full capacity of those drives on older operating systems, but the app isn't required for Windows 7 x64, which is the OS we expect most folks to be running with 6-series motherboards.

Native support for 3TB hard drives is one of EFI's most important features, and this bootloader approach appears to deliver the goods without replacing the entire BIOS.

https://techreport.com/news/20941/is-it-efi-or-not-gigabyte-hybrid-efi-bios-explained

How big is the hdd? that reaction seems odd, even if drive is bigger than 2,2tb Legacy should still see the hdd, it just can't use all of it. You should be able to install in legacy mode if you set it as boot method. It will just need you to delete GPT partitions as it can only boot off MBR.

Thanks again for the quick response!

I have rev4.0, flashed to F2. On gigabyte's website, I don't see an F4 flash, just F1-3 (https://www.gigabyte.com/Motherboard/GA-990FXA-UD3-rev-40#support-dl-bios).

The HDD is only 1TB. What's strange is I have a 500GB WD Blue which i can install Windows to (using MBR) and it works fine. However, I'm trying to avoid using that because it only has a 16MB cach opposed to 64.

EDIT: Seems I shot myself in the foot...the other hard drive doesn't seem to want to boot after installing to it anymore either.

 

[androbourne]

Just something to keep in mind. I believe that mobo actually has two BIOS's one primary and a failover if primary gets corrupted. If your primary BIOS is set to UEFI but corrupted, then it will fail over to the legacy BIOS which if happened, would stop you from booting on GPT partitions.

Boot into the BIOS and just double check there is no warnings/errors of corruptions as well just to be safe.

 

[Colif]

I had a headache yesterday, it could be I mistyped F4 instead of F3. F2 is release bios of revision 4.1, so might want to upgrade to F3 since its 2 years newer.

I have a question you can't answer. Why is it there are more revisions of the motherboard listed on your link compared to one I used. Your link shows 6 revisions, mine only 4.
Yours - https://www.gigabyte.com/Motherboard/GA-990FXA-UD3-rev-40#support-dl-bios
Mine - https://www.gigabyte.com/us/Motherboard/GA-990FXA-UD3-rev-40#support-dl-bios
I guess some revisions not released in US. I haven't seen that before.

The way dualbios works is your PC is never supposed to boot off 2nd one. What its meant to do is the second the PC doesn't boot due to corruption, it is meant to restart and the 2nd bios chip copies itself onto the 1st one and then restarts PC using main bios. Its just backup. - https://www.gigabyte.com/microsite/55/tech_081226_dualbios.htm

it is possible the default boot method on the 2nd bios is legacy given its age. So if it is fixing corruption, it might work one time and not next. Might need a new CMOS battery.