I just wanted tell you that I found someone else managed to install unmodified Windows 11 on the unsupported system. This might give a hint for MS's blocking mechanism for older systems:
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I was able to install the "leaked" Win11 version on, ironically enough, an 11 yr old HP Pavilion with an Intel Q8400 CPU. The trick is to not use the standard Windows installation procedure and instead "deploy" the Win11 "install.wim" file via Diskpart/DISM or a 3rd party installer (which I did).
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