HP ZBook won't recognize FAT32 (GPT) USB drives when set in UEFI Native :(

I'm not sure where this should really be posted as it is a combination of OS/Storage/Laptop issue.

I just got an HP Zbook 14" G2 on Friday.

My goal was to install Windows 7 on the laptop using UEFI.

It comes with Windows 7 Pro installed in legacy mode, but I figured I should be able to find a way to get it installed with UEFI enabled so I can eventually dual boot on another drive to Win 10.

It has a 256 GB SSD HP Z Turbo Drive (M.2 PCIe) and I installed an extra Samsung EVO 850 Pro to be available for Win 10.

After going into the BIOS and setting it to UEFI Native (No CSM), disabling Fast boot, and checking other various settings I cannot get this laptop to recognize ANY USB drive I plug into it with UEFI enabled.

I have formatted various USB 3.0 and 2.0 drives using Rufus and DiskPart - They are all obviously FAT32 and formatted using a GPT partition. I even tried using a Win10 installer that worked flawlessly for installing UEFI Win10 on an HP Spectre x360 - and for whatever reason this laptop refuses to acknowledge it as a boot option.

I have also done the necessary steps for preparing the Windows 7 installation media to be UEFI ready.

Now the kicker is that there is an option in the "Boot Options" too boot from an .efi file and it allows me to browse through the directories on these flash drives. I tried to just select bootx64.efi, but that doesn't work - probably because the Windows Installer isn't meant to initialize that way and I had a feeling that would be the case.

I did A LOT of googling the last two days and I just can't seem to find the caveat here. I'm getting to the point where I feel like I just need to accept that this laptop model was behind the curve and won't read USB drives set up for UEFI. I saw several threads on the HP forums where people cannot even get their Zbook to read CD/DVDs when set for UEFI.

Anybody here have any experience with this that might have a trick or two up their sleeves? I'd greatly appreciate any help!

Edit: I should add I did a BIOS update first thing and it actually reverted back from 1.15 to 1.14.

Edit#2: Updated BIOS to 1.16 from HP's website. Still no luck.

So after hours of tinkering I -finally- got it to boot to an EFI file to install Windows 7.

I had to "Clear SecureKeys" even though Secure Boot was never enabled - even by default. That's what was causing loading .efi files to error out with a generic "Windows Cannot Run" prompt that would then ask you to insert the original CD/DVD to complete repairs (which doesn't even apply here). It appears that when you are using UEFI you don't actually boot to your USB Drive or installation media, but instead load the .efi associated with whatever OS you want to install.

The only issue I now have is that I had to clear the HP_Tools partition in order to install with a GPT since it was setup as MBR. Doing so resulted in losing UEFI functionality (go figure) so I have to choose my boot drive each time I start up the laptop as it will not automatically choose the M.2 drive in UEFI and instead errors out and asks to install an OS.

I am now in the process of recreating the HP_Tools partition and reinstalling that functionality back onto the main drive - talk about a process... I can't imagine how a regular user could ever upgrade this laptop from Win 7 to Win 10 considering that it requires that partition to handle UEFI functions, but by default it is installed on an MBR partitioned drive.

I found a lot of information on this process here and this is where I figured out I needed to clear SecureKeys.

Sounds like the newest bios may still be a little buggy.

Earlier this summer I had to mess with secure keys an Asus socket 1151 board when I was trying to build a Hackintosh. It was my first experience with secure keys.

It was a pain to say the least. I've never touched on SecureKeys, but apparently you can lock the installations on this device so that someone can't boot to another OS via a flash drive without clearing the cache or setting the computer into legacy mode. I don't see how this is a security feature unless you password the BIOS, but even then I can't imagine it being that hard to clear the BIOS password.

I spent nearly all my free time this weekend just trying to get Windows 7 installed using UEFI. Feels like I haven't stopped working for 3 weeks now (because I literally have been putting in 50-60 hours then troubleshooting extra stuff at home off the clock).

Once I got the installer to initialize I was able to check if it was using UEFI via the setupact.log - which it was.

After I got Windows installed I used the HPSoftpaq downloader to source the drivers - low and behold even their catalog is out of date and I had to manually grab a few drivers directly from the HP Website. I don't even know why I bother trying to use their "tools" - it doesn't even give you a good representation of the "best/latest" driver available. You have to dig through the mess it populates.

I'm finally all up to date on drivers - the screen started flickering after using the Softpaq manager to update the video driver and that was the first sign I needed to just grab them off the web.

Now the only thing that kind of irks me is that Windows says the AMD FirePro driver I have installed from AMD's website says it isn't digitally signed. Not the end of the world, but I can't make that caution symbol go away.

Now the next challenge is to see if I can install WinTen on here while using CSM since I had to use UEFI Hybird to install Windows 7.