Intel CPU Microcode 20201110 and 20201118 regression on Intel Skylake and Intel Cascade lake Server CPU's

This document (000019800) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server 12

Situation

SUSE has received reports that on certain hardware equipped with the server chipset variants of the Intel Skylake and Intel Cascade Lake family CPU's, starting with microcode ucode-intel 20201110, up to the recent released microcode (ucode-intel 20201118 update) causes these machines to no longer boot.

Resolution

SUSE has released corrected CPU Microcode versions as detailed below :

SUSE Linux Enterprise Server 15 SP2 : 20201118-2.16.1
SUSE Linux Enterprise Server 15 SP1 : 20201118-3.45.1
SUSE Linux Enterprise Server 12 SP5 : 20201118-3.29.1
SUSE Linux Enterprise Server 12 SP4 : 20201118-13.84.1
SUSE Linux Enterprise Server 12 SP3 : 20201118-13.84.1
SUSE Linux Enterprise Server 12 SP2 : 20201118-13.84.1

(Corrected versions for some products are yet to be released.)

Before the release of the corrected versions, the workaround was to revert to Intel CPU Microcode release 20200616, released in June 2020, as per the SUSE updates listed below:

SUSE-RU-2020:1700-1
SUSE-RU-2020:1702-1
SUSE-RU-2020:1703-1
SUSE-RU-2020:1802-1

Cause

The problem is reported to be caused by Intel CPU Microcode upgrades 20201110 and 20201118 for the server chipset variants of the respective CPU families.

Affected firmware revisions are:

Sky Lake : 0x2006a08
Cascade Lake: 0x4003003 and 0x5003003

Disclaimer

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