I have an MSI Z170A SLI Plus motherboard and an Intel Core i5-6600K CPU. I decided to upgrade to BIOS from 1.6 to 7998v1E. After this, all version of Linux I tried to boot failed with "Processor context corrupt" complaining about Core 2. Windows can boot but crashes shortly after. After some trial and error I found that I could boot if I disable 2 cores out of 4.
I tried to downgrade the BIOS and to reset the CMOS but it didn't fix the problem. Is my processor or mainboard damaged somehow, or some internal memory corrupted? Is there any way out of this or am I stuck with half a CPU?