T61 cpu in a T60?

[RealBlackStuff]

Need to go a step back in history, since I just remembered that phlash16.exe requires DOS, not Windows.
Make a DOS-bootable USB stick using e.g. Rufus: https://rufus.akeo.ie/
Copy those extracted files from .rar onto it (including the renamed BIOS.WPH).
Then insert the USB stick, boot the laptop and immediately press F12.
Select Boot from USB-HDD.
You'll be booting into DOS, where it might ask for UK- or US-English keyboard.
Type phlash16.exe and hit Enter.
And done!

[mbr12]

I just installed the cpu and N adapter. No error code and the device manager recognizes the hardware changes.
Go figure.