Able to install W11 in Hyper-V Gen 1 machine?

jabbado · Sep 28, 2022

I've recently started using Hyper-V for running test environments after using VMware for years.

The other day I decided to try installing windows 11 on a VM. I created an iso of 21H2 (build 1042) using the uupdump.net site.
Being new to Hyper-V I created a Gen 1 machine. The W11 build installed without a hitch and I was able to create a native boot vhdx from it.

Then yesterday I dowloaded the 22H2 iso from Microsoft and tried the same thing. But it would not install due to the TPM 2 requirements etc.
After reading a few guides it seems all W11 versions need to be installed on a Gen 2 VM.

My simple question is: why can I install from the 21H2 iso to a Gen 1 VM when it should be locked down as well?

cereberus · Sep 28, 2022

jabbado said:
I've recently started using Hyper-V for running test environments after using VMware for years.

The other day I decided to try installing windows 11 on a VM. I created an iso of 21H2 (build 1042) using the uupdump.net site.
Being new to Hyper-V I created a Gen 1 machine. The W11 build installed without a hitch and I was able to create a native boot vhdx from it.

Then yesterday I dowloaded the 22H2 iso from Microsoft and tried the same thing. But it would not install due to the TPM 2 requirements etc.
After reading a few guides it seems all W11 versions need to be installed on a Gen 2 VM.

My simple question is: why can I install from the 21H2 iso to a Gen 1 VM when it should be locked down as well?

Earlier versions were more relaxed. MS have been tightening things up.

jabbado · Sep 28, 2022

cereberus said:
Earlier versions were more relaxed. MS have been tightening things up

But was this possible only within a Hyper-V machine? Because I'm sure I couldn't get an earlier w11 iso to install in Vmware without enabling UEFI/TPM etc.

Bree · Sep 28, 2022

jabbado said:
I dowloaded the 22H2 iso from Microsoft and tried the same thing. But it would not install due to the TPM 2 requirements etc.
After reading a few guides it seems all W11 versions need to be installed on a Gen 2 VM.

A Gen 1 Hyper-V machine is a Legacy bios/MBR machine, a Gen 2 machine is a UEFI/GPT machine.

It makes no difference whether a machine is virtual or physical, Windows 11 requirements are for a UEFI/GPT machine that supports secure boot, at least 4GB RAM, a supported processor and TPM 2.0.

Likewise, it is perfectly possible with some known workarounds to install Windows 11 on any unsupported Legacy bios/MBR machine. You can install 11 on a Gen 1 machine if you really need to, you'll just need to use the same workarounds as for any other unsupported device.

jabbado · Sep 28, 2022

Bree said:
It makes no difference whether a machine is virtual or physical, Windows 11 requirements are for a UEFI/GPT machine that supports secure boot, at least 4GB RAM, a supported processor and TPM 2.0.

Then I'm confused. I know about the workarounds and have tried some of the patching methods in VMware.
However this is an unpatched iso of 21H2 created from the uupdump site three days ago. I just installed it again in a new Gen 1 machine:

How is this possible then?

hsehestedt · Sep 28, 2022

Copy the following to a text file and the name file whatever you want with a ".REG" extension. I'll just assume "bypass_win11_requiremenets.reg".

Code:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\Setup\LabConfig]
"BypassTPMCheck"=dword:00000001
"BypassSecureBootCheck"=dword:00000001
"BypassRAMCheck"=dword:00000001
"BypassStorageCheck"=dword:00000001
"BypassCPUCheck"=dword:00000001

Drop "bypass_win11_requiremenets.reg" onto the root of you Windows ISO image.

Start installation as usual to HYPER-V as a gen 1 system. As soon as Windows setup pauses at the first static screen, press SHIFT + F10 to open a command prompt.

In the command prompt, navigate to the install disk and run "bypass_win11_requiremenets.reg".

Continue installation as normal. It should install just fine.

Edit: If you don't want to re-create your ISO image with the above file, then simply run the appropriate registry commands below from the command prompt when you get to the first static screen like this:

reg add HKLM\System\Setup\LabConfig /v BypassTPMCheck /t reg_dword /d 0x00000001 /f
reg add HKLM\System\Setup\LabConfig /v BypassSecureBootCheck /t reg_dword /d 0x00000001 /f
reg add HKLM\System\Setup\LabConfig /v BypassRAMCheck /t reg_dword /d 0x00000001 /f
reg add HKLM\System\Setup\LabConfig /v BypassStorageCheck /t reg_dword /d 0x00000001 /f
reg add HKLM\System\Setup\LabConfig /v BypassCPUCheck /t reg_dword /d 0x00000001 /f

jabbado · Sep 28, 2022

hsehestedt said:
Copy the following to a text file and the name file whatever you want with a ".REG" extension. I'll just assume "bypass_win11_requiremenets.reg".
............

No, I'm not asking how to get it to install. I'm saying I can install using this "legit" iso into a gen 1 VM without any patching whatsoever and would like to know why?

cereberus · Oct 4, 2022

jabbado said:
No, I'm not asking how to get it to install. I'm saying I can install using this "legit" iso into a gen 1 VM without any patching whatsoever and would like to know why?

Well, I have just tried to install 22H2 in gen 1 and it does not let me.

As I said, MS were more lenient on initial release.

jabbado · Oct 4, 2022

cereberus said:
Well, I have just tried to install 22H2 in gen 1 and it does not let me.

Yeah. It was pointed out to me on another forum also, that the 21H2 version I downloaded may have been a preview release and some of those will install on non-complient hardware. I don't know how true that is.

cereberus · Oct 4, 2022

jabbado said:
Yeah. It was pointed out to me on another forum also, that the 21H2 version I downloaded may have been a preview release and some of those will install on non-complient hardware. I don't know how true that is.

Well, there are only two possible answers

True

or

False

If False, then you could not have installed it. Thus the answer must be true.