UEFI BIOS can only boot from Windows 8-based install media?????

[ebm9000]

*long post ahoy!*

Hello. I own an Unbranded UB-15MS10 Tablet I got from Best Buy a while ago. 32 GB Storage, 2 GB RAM, Atom Bay Trail processor, yada yada yada. Anyhow, Unless the USB device I use (booting it form the port on the keyboard dock) has Windows 8 based media on it, IT WILL NOT BOOT! The Flash Drive is being formatted GPT, but When I put, oh, say Windows 7 Install Media on it, I click it in the BIOS and it just blinks and goes back to BIOS. Flash drive is formatted GPT that time aswell, and there is nothing wrong with it. Same for Android, or Linux, etc. The Tablet can only boot from GPT media apparently I learned. Ok, Well why is it that when I put a Windows 8 32 or 64 bit image on the drive that it boots just fine, but when I try a 32/64 bit image of Windows 7, Linux, etc, it will not boot? I do not get it! I have tried substituting the INSTALL.WIM file on the Windows 8 disk with the Windows 7 one but I get "Windows could not prepare the computer for the next phase of installation" at the very end of install. Very fustrating. Do the new tablets have a Windows 8 only no matter what requirement now? The only exception is a random Debian USB drive I had. I tried to boot it and I got a Secure Boot Violation. I turn that off and it actually boots, but fails to install b/c it cannot be installed from a USB (thinks it needs a non-existent CD-ROM drive).

To sum it up:
-Why does only Windows 8 media boot on the machine?
-What am I doing wrong when trying to boot anything else on it?
-The Flash drive is GPT formatted, and I have used Unetbootin, Rufus, Windows 7 USB DVD tool, and the Command Prompt to try and format it. Very fustrating 🙁

 

[Shaun o]

Windows 7 is limited to a max partition size of 2 Tb when using the NTFS formatting.
GPT allows a Max drive size or a single partition to be 4TB in size.

The problem is with the 32 GB storage and it being formatted to GPT, but windows 7 likes to use NTFS by default when you click next.

To manually wipe a drive, storage memory or space of a Tablet. and convert it to GPT:

Turn off the PC, and put in the Windows installation DVD or USB key.
Boot the PC to the DVD or USB key in UEFI mode. For more info, see Boot to UEFI Mode or Legacy BIOS mode.
From inside Windows Setup, press Shift+F10 to open a command prompt window.
Open the diskpart tool:
diskpart
Identify the drive to reformat:
list disk
Select the drive, and reformat it:
select disk <disk number>
clean
convert gpt
exit
Close the command prompt window.
Continue the Windows Setup installation.
When choosing an installation type, select Custom. The drive will appear as a single area of unallocated space.
Select the unallocated space and click Next. Windows begins the installation.

 

[Paul NZ]

And secureboot is probably enabled on it. Win7 32 bit doesnt support it. So you would have to change it to legacy boot

 

[ebm9000]

Windows 7 is limited to a max partition size of 2 Tb when using the NTFS formatting.
GPT allows a Max drive size or a single partition to be 4TB in size.

The problem is with the 32 GB storage and it being formatted to GPT, but windows 7 likes to use NTFS by default when you click next.

To manually wipe a drive, storage memory or space of a Tablet. and convert it to GPT:

Turn off the PC, and put in the Windows installation DVD or USB key.
Boot the PC to the DVD or USB key in UEFI mode. For more info, see Boot to UEFI Mode or Legacy BIOS mode.
From inside Windows Setup, press Shift+F10 to open a command prompt window.
Open the diskpart tool:
diskpart
Identify the drive to reformat:
list disk
Select the drive, and reformat it:
select disk <disk number>
clean
convert gpt
exit
Close the command prompt window.
Continue the Windows Setup installation.
When choosing an installation type, select Custom. The drive will appear as a single area of unallocated space.
Select the unallocated space and click Next. Windows begins the installation.

Yes, but:

Only Windows 8 media can boot, but not a problem since once Win8 setup is booted, I can swap drives because image I in system RAM. Only problem now is that Windows 7 "cannot prepare the computer to boot into the next phase of installation". At the very end of the install, and occasionally setup says this computer may not be able to boot from it, check your BIOS settings, etc.