Win7 pure UEFI booting issue  

Hi all.

I'm in the process of trying to get Win7 going on a pure UEFI system, and I'm at the last hurdle, getting graphics output.

As it stands, the install will boot and work fine with CSM enabled, but won't initialize either of my displays without CSM.

I installed the OS through pure UEFI with the Win10 installer, with all the drivers I could pre-packaged. I then backed down to CSM and got the install finished with graphics drivers and updates.

In my attempt to get rid of CSM, I've disabled in regedit/renamed vga.sys and vgapnp.sys, and transplanted the Win10 EFI loaders in place of 7's. I tried both UefiSeven and VgaShim, both of which gave their output but would still hang on the splash screen. Neither of these reported fatal errors. I also tried booting through EfiGuard (without secure boot), which gives the same results as UefiSeven and VgaShim.

It may be completely irrelevant, but on boot widows fails to load dxgkrnl.sys. This seems to only happen without CSM.

I have tried numerous different versions of the drivers for my GPU, and I'm currently on 20.1.4. 21.5.2 and a load of other versions above 20.1.4 cause my primary display to be stuck solid blue, and I tried other older ones all the way down to the release drivers to no avail. I also tried utilizing DevManView with a batch script to restart the drivers upon logging in, but it did seemingly nothing.

Fast boot is off, as is secure boot.

When booting in pure UEFI, the system doesn't crash, however; if I type my login numlock will turn itself on, as it does normally, which should mean the OS is booting. Additionally, audio doesn't come through HDMI.

I think I might be missing something, or perhaps there's a problem to doing this with a newer AMD GPU.

Thanks.

bouboodi said:

Hi all.

I'm in the process of trying to get Win7 going on a pure UEFI system, and I'm at the last hurdle, getting graphics output.

As it stands, the install will boot and work fine with CSM enabled, but won't initialize either of my displays without CSM.

I installed the OS through pure UEFI with the Win10 installer, with all the drivers I could pre-packaged. I then backed down to CSM and got the install finished with graphics drivers and updates.

In my attempt to get rid of CSM, I've disabled in regedit/renamed vga.sys and vgapnp.sys, and transplanted the Win10 EFI loaders in place of 7's. I tried both UefiSeven and VgaShim, both of which gave their output but would still hang on the splash screen. Neither of these reported fatal errors. I also tried booting through EfiGuard (without secure boot), which gives the same results as UefiSeven and VgaShim.

It may be completely irrelevant, but on boot widows fails to load dxgkrnl.sys. This seems to only happen without CSM.

I have tried numerous different versions of the drivers for my GPU, and I'm currently on 20.1.4. 21.5.2 and a load of other versions above 20.1.4 cause my primary display to be stuck solid blue, and I tried other older ones all the way down to the release drivers to no avail. I also tried utilizing DevManView with a batch script to restart the drivers upon logging in, but it did seemingly nothing.

Fast boot is off, as is secure boot.

When booting in pure UEFI, the system doesn't crash, however; if I type my login numlock will turn itself on, as it does normally, which should mean the OS is booting. Additionally, audio doesn't come through HDMI.

I think I might be missing something, or perhaps there's a problem to doing this with a newer AMD GPU.

Thanks.

For pure Uefi Boot, you need to install Windows 7 in GPT partition and not in MBR as default......
In mine I have "enabled Fast Boot" without problems, the important that you disable the "Secure Boot".

Cris85 said:

For pure Uefi Boot, you need to install Windows 7 in GPT partition and not in MBR as default......
In mine I have "enabled Fast Boot" without problems, the important that you disable the "Secure Boot".

It is installed under a GPT partition, as the first install was done without CSM.

@booboudi

I tried both UefiSeven and VgaShim, both of which gave their output but would still hang on the splash screen

I'm unclear as to whether you tried these patches with CSM on or off. But hanging on the splash logo at boot indicates that the older vga requirement for Int10h has not been circumvented (which both UefiSeven and VgaShim are meant to do, of course).

I haven't done this with an AMD GPU, only Intel. There should be no difference for the circumvention of Int10h on boot, though. Either UefiSeven, VgaShim (and even FlashBoot) will do that. Later application of specific GPU drivers above vga can be difficult as the PCI-PCIe bridge on newer motherboards is not standardised, so Win7 may have several resource conflicts.

Can you detail your explicit sequence for booting, or failing to boot, with CSM off ? Does your installation pre-package include advanced GPU drivers ?

To help sort out the likely conflicts, I've found it useful to use an independent Win10PE USB boot with as many utilities on it as can be fitted. Like a big Swiss Army knife. A 10 minute search will find these ISO's for download (with care).

ian50 said:

@booboudi

I tried both UefiSeven and VgaShim, both of which gave their output but would still hang on the splash screen

I'm unclear as to whether you tried these patches with CSM on or off. But hanging on the splash logo at boot indicates that the older vga requirement for Int10h has not been circumvented (which both UefiSeven and VgaShim are meant to do, of course).

I haven't done this with an AMD GPU, only Intel. There should be no difference for the circumvention of Int10h on boot, though. Either UefiSeven, VgaShim (and even FlashBoot) will do that. Later application of specific GPU drivers above vga can be difficult as the PCI-PCIe bridge on newer motherboards is not standardised, so Win7 may have several resource conflicts.

Can you detail your explicit sequence for booting, or failing to boot, with CSM off ? Does your installation pre-package include advanced GPU drivers ?

To help sort out the likely conflicts, I've found it useful to use an independent Win10PE USB boot with as many utilities on it as can be fitted. Like a big Swiss Army knife. A 10 minute search will find these ISO's for download (with care).

Both UefiSeven and VgaShim were tried with CSM on and off (I am aware it's pointless with CSM, but did it for testing purposes), neither of which got the system to boot properly. With CSM on and VGA Output enabled, UefiSeven does freeze at "Starting Windows" but the animation continues, as the system doesn't lock up.

With CSM off, upon booting windows, the boot drivers for my keyboard and mouse are unloaded, take a few seconds, then the windows ones load. Since I have VGA output disabled I see nothing else during this time, but the fact that the keyboard and mouse turn on again indicates that the system is at minimum loading their drivers. And, as mentioned in the first post, if after my keyboard lights up again, I type in my password, the system seems to unlock, as NumLock will then turn itself on.

The installer itself did not have GPU drivers pre-packaged; the system was installed without CSM, then CSM was turned on to get to the desktop, at which point GPU drivers were installed, and I figured at that point I'd be good. Is there a difference to having them loaded into install.wim vs doing it that way?

My install method uses the Win10 installer, with install.wim replaced with my modified one.

Your PCI-PCIe bridge suggestion may be a problem, however; with CSM enabled so I can get into Windows properly, device manger reports a few PCI-related deivces that couldn't find drivers. Of couse the system works without them under CSM but they may be the culprit for non-CSM. Two devices named "PCI Device", and one named "PCI Encryption/Decryption Controller".

Should go without saying, thank you both for the input so far. This forum is priceless.

- - - Updated - - -

Upon further investigation, the PCI Encryption/Decryption controller and the two PCI Devices seem to really be three failing PCI-to-PCI Bridge (thanks to HWINFO64, also called "Internal PCIe GPP Bridge").

I tried getting windows to double check the folder I have of chipset related drivers for it, to no avail.

Win7 is trying to load drivers to these that coorespond to the "PCI Express standard Root Port", and is failing.

- - - Updated - - -

Another update, reinstalled the chipset drivers fresh from AMD, and it fixed those errors. Will reboot without CSM and update.

- - - Updated - - -

No change in function. I guess it's good I sorted that issue, but it still won't cooperate without CSM.