Microsoft works weekends to kill Intel's shoddy Spectre patch
https://www.theregister.co.uk/2018/01/29/microsoft_out_of_band_patch_to_remove_spectre_patches/
Microsoft has implemented Intel's advice to reverse the Spectre variant 2 microcode patches.
Redmond issued a rare weekend out-of-cycle advisory on Saturday here, to make the unwind possible.