GitHub user Zeffy has created a patch that removes a limitation that Microsoft imposed on users of 7th generation processors, a limit that prevents users from receiving Windows updates if they still use Windows 7 and 8.1.

This limitation was delivered through Windows Update KB4012218 (March 2017 Patch Tuesday) and has made many owners of Intel Kaby Lake and AMD Bristol Ridge CPUs very angry last week, as they weren't able to install any Windows updates.

Microsoft's move was controversial, but the company did its due diligence, and warned customers of its intention since January 2016, giving users enough time to update to Windows 10, move to a new OS, or downgrade their CPU, if they needed to remain on Windows 7 or 8.1 for various reasons.

When the April 2017 Patch Tuesday came around last week, GitHub user Zeffy finally had the chance to test four batch scripts he created in March, after the release of KB4012218.

His scripts worked as intended by patching Windows DLL files, skipping the CPU version check, and delivering updates to Windows 7 and 8.1 computers running 7th generation CPUs.

Patches have been open-sourced on GitHub

The four batch scripts are now available on GitHub, open-sourced and ready to be inspected, just in case anyone fears Zeffy might have disguised any malware.

According to Zeffy's README file, he created the four batch scripts by reverse engineering the KB4012218 Windows Update, and comparing versions of the new files with the ones already on his PC.

By running a simple diff operation on these files, he was able to discover two new functions "IsCPUSupported(void)" and "IsDeviceServiceable(void)" inside the March 2017 version of wuaueng.dll, delivered through KB4012218.

Zeffy's scripts patch this DLL file and make the two functions output "1", which translates to "supported CPU." This, in turn, starts the update procedure, delivering new security updates to users Microsoft wanted to block.

"The only downside of these solutions is you have to apply a new patch whenever wuaueng.dll gets updated," says Zeffy in his GitHub repo README. Fortunately, the entire task doesn't take long to complete.

Bleeping Computer hasn't tested Zeffy's patch because we don't have a 7th-gen CPU on hand. It's recommended that you create a system restore point and save a copy of the original wuaueng.dll file just in case things go horribly wrong.