This update supersedes microcode provided  by Red Hat with the CVE-2017-5715 (“Spectre”)

 CPU branch injection vulnerability mitigation. (Historically, Red Hat has provided updated

 microcode, developed by our microprocessor partners, as a customer convenience.) Further

 testing has uncovered problems with the microcode provided along with the “Spectre” mitigation

 that could lead to system instabilities. As a result, Red Hat is providing an microcode update

 that reverts to the last known good microcode version dated before 03 January 2018.

 Red Hat strongly recommends that customers contact their hardware provider for the latest microcode updates.

 IMPORTANT: Customers using Intel Skylake-, Broadwell-, and Haswell-based platforms must obtain and

 install updated microcode from their hardware vendor immediately. The "Spectre" mitigation requires

 both an updated kernel from Red Hat and updated microcode from your hardware vendor.