Allow GPT Boot USB Drives

[MattC1]

Hi,

I have a HP EliteDesk 800 G1 SFF desktop and want to boot from a USB drive.  If I load a bootable drive formatted with MBR the boot loads.  However, I can't get one formatted with GPT to load.  I assume that there is some switch in the bios that I can flick to allow this, but I can't find one.  Am I mistaken?

Matt

[Paul_Tikkanen]

Hi, Matt:

Use the free Rufus utility to create a bootable W10 USB installation flash drive.

Set the Rufus menu up exactly as you see it in the illustration for Windows installations.

Rufus - Create bootable USB drives the easy way

After the drive has been successfully created, you boot the flash drive from the EFI USB boot source, not the legacy one.

[MattC1]

Thank you for your response.  The USB drive actually holds RescueZilla and no settings in Rufus seem to allow this ISO to be transferred with MBR.  This is why I was hoping to access the drive using GPT.  Is this computer able to do that, or is it MBR only?

[Paul_Tikkanen]

You're very welcome. 

The PC supports booting from both GPT and MBR.

To boot GPT, you have to boot the USB flash drive from the PC's F9 EFI USB flash drive boot option, not the legacy one.

[MattC1 · Accepted solution]

The GPT drive is not coming up in the 'UEFI Boot Sources' options, just the 'Legacy' ones.  Is there a setting that I have to change in the BIOS?

Edit:

Just figured it out:  In the 'Setup Utility' (F10 on Startup), under 'Storage' > 'Boot Order', the section 'UEFI Boot Sources' was greyed out.  I had it disabled.  Selecting the UEFI line and clicking F5 reenabled it.  F10 to Accept and 'File' > 'Save Changes and Exit' solved the problem.  Booting from the GPT USB drive through F9 is no possible.

Thanks for any assistance.

Matt

[Paul_Tikkanen]

The only suggestion I can offer would be to plug the USB flash drive into one of the USB 2 ports instead.

I have the 2 generations older 8200 Elite CMT and the PC would not boot from a USB flash drive in UEFI mode unless I plugged it into the second USB port from the top.

Don't have a clue why that is but since I have two of the same PC's they both worked the same way, so it was not a fluke.

The 8200 Elite series have no USB 3 ports at all.

So, try some different USB ports than the one you are using.