Comment 2 for bug 1879077

I see two problems.

1. You have a very old kernel installed (3.13.0-38), which is causing this message: "E: amd64-microcode: unsupported kernel version!" I'm not sure if this is causing update-initramfs to fail, but if you don't need this kernel you should just remove it.

2. These messages:

  E: /usr/share/initramfs-tools/hooks/casper-memdisk failed with return 1.
  update-initramfs: failed for /boot/initrd.img-3.13.0-38-generic with 1.

Again, this may go away if you remove the old kernel. However it also seems like it should not fail like this, so I've added casper to the bug.

Neither of these is a problem with linux-firmware. Rather, linux-firmware triggers an initramfs update, and other packages are causing the initramfs update to fail.