Intel: microcode-20180108.tgz
AMD: Debian package amd64-microcode_3.20171205.1.tar.xz pulled 11 Jan 2018
This is the same as linux-firmware master, plus one more file 
microcode_amd_fam17h.bin which needs the following kernel:
Linux 4.15, 4.14.13, 4.9.76, 4.4.111, and later.

