[Bug 1882890] Re: intel-ucode/06-4e-03 from release 20200609 hangs system in early boot

[Henrique de Moraes Holschuh]

So, according to Intel, the probable cause for 0x406e3 and 0x506e3
processors to fail loading the microcode update *early* is an
incompatibility when you update from a very old microcode release in
BIOS/UEFI (BIOS has a revision older/smaller than 0x80) to the newer
microcode updates.

This information was provided by Intel in the upstream bug report:
https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/31#issuecomment-761228960

However, it looks like it could have been fixed by the latest microcode
update batch, from 20210608, which contains microcode revision 0xea for
the 0x406e3 and 0x506e3 processors.

It would be extremely helpful if anyone that had this issue could test
the 20210608 microcode update and report, please.  It helps if you
include the contents of /proc/cpuinfo *without* the microcode update,
and then the contents of /proc/cpuinfo *with* the microcode update
installed.

Thank you!

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https://bugs.launchpad.net/bugs/1882890

Title:
  intel-ucode/06-4e-03 from release 20200609 hangs system in early boot

Status in intel-microcode package in Ubuntu:
  Fix Released
Status in intel-microcode source package in Xenial:
  Fix Released
Status in intel-microcode source package in Bionic:
  Fix Released
Status in intel-microcode source package in Eoan:
  Fix Released
Status in intel-microcode source package in Focal:
  Fix Released

Bug description:
  Hi,

  This morning I applied the latest updates on my Ubuntu 16.04 (kernel
  4.15.0-106-generic + intel-microcode 3.20200609.0ubuntu0.16.04.0) and
  rebooted as usual to boot on the new kernel but the system won't boot:
  black screen.

  I tried booting the previous kernel 4.15.0-101 and it seems to be the
  same : in grub I select the 4.15.0-101 kernel, press enter, a message
  "Loading initrd..." is printed but nothing else happens.

  Tried even older kenrel 4.4.0-184-generic : same problem, "Loading
  initrd...", and nothing happens.

  I managed to boot a 4.4.0-142-generic, but bluetooth and wifi are non-
  functionnal.

  I mounted the /boot partition from a USB rescue drive, and it seems that all the initrd images that got updated this morning are not bootable anymore :
  - initrd.img-4.15.0-106-generic
  - initrd.img-4.15.0.101-generic
  - initrd.img-4.4.0-184-generic

  I tried regenerating the images with update-initramfs but it's the
  same : "Loading initrd" message but nothing happens.

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