Comment by rlpb

> RHEL/CentOS/Fedora have been providing processor microcode updates for ages now and with relatively frequent updates (see the microcode_ctl RPM changelog)

I wasn't aware of this, thanks. Though I searched, and I found that they've been causing their users problems by doing so: https://rhn.redhat.com/errata/RHBA-2017-0028.html

I think this backs up my point: care must be taken.