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aaazen 08-15-2016 11:31 AM

Linux-4.8-rc2 fails reading AMD microcode, /boot/amd-ucode.cpio
On Slackware-current, I run this script to create a /boot/amd-ucode.cpio file:

#! /bin/sh
set -x
set -e


echo "Create the $CPIO file from the $LIB directory of files"
rm -rf  /tmp/amd-ucode-cpio
mkdir -p /tmp/amd-ucode-cpio
cd      /tmp/amd-ucode-cpio
mkdir -p  $TDIR
find $LIB -type f -name \*bin | sort | xargs cat > $TDIR/AuthenticAMD.bin
find . | cpio --no-absolute-filenames -H newc -o -F $CPIO


echo "Concatenate $CPIO and /boot/initrd-4.4.15.gz creating /boot/initrd.gz"
cat $CPIO /boot/initrd-4.4.15.gz > /boot/initrd.gz

When I use the /boot/amd-ucode.cpio with the Linux-4.8-rc2 kernel the system immediately reboots with no error messages.

The /boot/amd-ucode.cpio file works fine with other kernels version 4.7 and older.

Here is my lilo entry for 4.8-rc2:

# Linux bootable partition config begins
image = /boot/vmlinuz-huge-4.8-rc2
  initrd = /boot/amd-ucode.cpio
  root = /dev/sda8
  label = linux-huge-4.8
  read-only  # Partitions should be mounted read-only for checking
#  addappend="console=ttyS0,38400"
# Linux bootable partition config ends

Version 4.8-rc1 fails too in the same way.

I tested 4.8-rc2 with the Intel microcode, /boot/intel-ucode.cpio and it boots fine.

The intel microcode can be created by installing the iucode-tool and intel-microcode packages from

aaazen 08-22-2016 08:33 AM

This is now fixed in linux 4.8-rc3

Thanks to all the kernel developers!

Update 14:59 UTC:

Kernel patch:

Kernel announcement:

All times are GMT -5. The time now is 09:51 AM.