Yeah, the article says “patch”, but I don’t really think that microcode is patchable - it’s burnt into the chip AFAIK.
Microcode is patchable on many issues.
The Floating point bug, for instance was not patchable as when the error occurred, it did not throw an exception flag.
It was a fundamental logic bug which required a re-design to correct.
You would be surprised at how many design errors have been fixed by using microcode updates on Intel processors.
I used to work for them in design