Dual boot MB; 1 MBR, 1 GPT drives, GPT won't boot, same O/S

[videobruce]

Specs;
Gigabyte GA-970A-D3P Rev 2 older MB (2016) AMD based system.

Main drive; 250GB SSD W7 Pro x64 MBR no hidden partitions

Backup; brand new 4TB same O/S GPT one created System partition using Disk Part .

Backup is seen in the Bios, but won't boot even if the SSD is disconnected. The MB is advertised as "dual boot". No custom settings, no overclocking etc. I've tried different Boot settings, the few that are there and no difference. The system always boot to the MBR. I haven't reset the Bios since I don't do custom settings, but I considered it.

The original system was the SSD and 2TB MBR Backup drive (no hidden partitions), same O/S's and that worked for eight years. Both drives have other storage partitions.

Any other details, please ask. The basic difference is one MBR and one GPT drive.

Here is the Bios boot mode select screen.

 

[:D:D]

IIRC W7 cannot boot UEFI GPT, you need W8 or higher boot EFI files on the system partition and even then there's caveats.

 

[videobruce]

At one point the GPT disk did boot, but I had to disconnect the SSD drive to do so.

 

[Calenhad]

What is the Storage Boot Option Control set to? Legacy first?

 

[videobruce]

It was at legacy. I did I change it to UEFI First, thou it didn't matter, the Bios just ignores the UEFI/GPT drive.

 

[agent_x007]

IIRC W7 cannot boot UEFI GPT, you need W8 or higher boot EFI files on the system partition and even then there's caveats.

It can, it's just a pain to setup right (if you are allergic to moded installer images)

Main drive; 250GB SSD W7 Pro x64 MBR no hidden partitions

Backup; brand new 4TB same O/S GPT one

Also, you can't do a 1:1 backup on MBR style, and expect it to boot from GPT drive (without tweaks/modifications).

Honestly, just install clean Windows on GPT and try to restore it from MBR version.
Not sure how many system files are replaced under such circumstances, but it's worth a shot (maybe boot sector will be kept unchanged). After restore is complete, then make a new 1:1 backup this time with working GPT (I assume, above method works). Again, this GPT drive backup will not boot from MBR drive.

EDIT : Also, make sure to disable Secure Boot (if it's an option), or you will face security key issues down the line.

 

[videobruce]

I was tiring to avoid a fresh install for the new Backup 4TB drive, but it's crossed my mind more than once. It's the customazing that I don't like since it seems endless..

 

[:D:D]

It can, it's just a pain to setup right (if you are allergic to moded installer images)

Just to be clear, W7 can be booted using W8 and higher EFI boot files but if you have a way to do it just with W7 then maybe that's the better way to go.

EDIT : Also, make sure to disable Secure Boot (if it's an option), or you will face security key issues down the line.

Good point. I'm having trouble remembering so hopefully you can help @videobruce