[SOLVED] Can\'t install Windows 7 on UEFI Class 3

Hey guys! I want to install Windows 7 on my Mac Pro 5,1 but the install just wont boot. I am using OpenCore bootloader as a boot menu to have a boot screen on macOS or load GRUB. The graphics card I have built is an RX 580. I have tried using a guide on youtube (look up install windows 7 dism method) to install Windows 7 and make my own installer ISO using Integrate7 but none of these methods worked. Is there a way I could end up with a working windows 7 install?

@formerlychucks

you need this - https://github.com/manatails/uefiseven

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Ok, I will try that method. I’ll get back to you if it works.

won’t work, stuck at starting windows @infuscomus

@formerlychucks

contact the developer on github, they should be able to help you.

found out why it doesn’t work, it fails to unlock the C0000:CFFFF address space. the issue lies in the graphics card vbios.

EDIT: doesnt necessarily have to be the vbios

hmm, I could just patch the vga address in the source code.

does anyone know where the vga rom address space is located? I tried 0x80000 but it did not work

EDIT: successfully patched the uefiseven driver, thx for showing me that tool :smiley:

Hi @formerlychucks
Thanks or the post and letting others know that this is fixed. However it looks like the fix is a customized one. May I request you to please add what you did? Where did you patch or hardcode the address and how you rebuilt the module? This may help others facing similar issues in future.
Thanks

@formerlychucks How you patched the UefiSeven in order to successfully boot Windows 7, Vista and Server 2008 (R2) in UEFI w/o CSM?

Can you please say how you patched it? everytime i try to find a way to fix this problem i always find people that either weren’t able to fix it or they fixed it but didn’t share the solution, i just gave up on a laptop i had but if you tell me how to fix that problem then i will try to install win 7 back on it.
@formerlychucks

I also want to patch Win7 on UEFI3.0 without CSM Support. Could you pleace tell us how you fixed it? Thanks!

I found out that in VbeShim (the code that VgaShim and UefiSeven is based of) has the vga rom address space set to A0000 instead of C0000.
Try to compile UefiSeven with this change and see if this works.
I don’t know how to compile UefiSeven no matter how much I tried so If you know how to compile UefiSeven, then you’re lucky.

Hello, there is no need as i found someguy who gave the bootx64.efi from a paid program called Flashboot Pro for free, anyway i was able to install windows 7 with ethernet and usb fully working but the laptop has an RTX 3050 Ti as the GPU and Nvidia only provides Windows 7 drivers for the non Ti versions.
Editing the .Inf of the driver to force the install worked but the Gpu didn’t actually work so i just kept Windows 10 on that laptop and im not using that laptop since like 2020 lol

if you need it to install Windows 7 on a laptop that doesn’t have CSM then i can share this file with you, it works very well.
But unless your laptop has Gpu drivers for Windows 7 (such as laptops with Nvidia MX cards or RTX 30 series non-ti) then it’s useless to install it, also your device must support disabling the Integrated Gpu (such as Intel Iris, or Amd Radeon) because new IGPU do not have any drivers for Windows 7, and since Laptops use the IGPU to output the Dedicated GPU video to the screen, you will not be able to use your Gpu if your device doesn’t support disabling the IGPU first (this feature is also called a MUX Switch if im not wrong).
So yeah, if you want a good Win 7 “modern” laptop you need to use an Intel 7th gen max computer with a dedicated Gpu (8th gen also works, as you can install a modded gpu driver if im not wrong)

On desktop it’s another deal, you can get Windows 7 on any modern cpu / gpu, just make sure you have an Asus or MSI motherboard as Gigabyte and Asrock give an ACPI 0xA5 BSOD when trying to install Win 7.

Hello @jonny jonny can you send me the bootx64.efi

Yes, here it is, extract it on your Win 7 USB in the “efi\boot” folder and rename it to bootx64.efi

FLASHBOOT-BOOTMGFW.EFI -WINDOWS 7 NO CSM (GOP BOOT).zip (389.8 KB)