Stuck on "Loading initial ramdisk..." after upgrading

Question

Running Ubuntu on a Zenbook Pro 14 UX480FD. Its been working okay for the past months but since running sudo apt update && sudo apt upgrade just earlier the other day, it's stopped booting correctly. GRUB loads fine but booting to any linux distro freezes after Loading initial ramdisk.... Recovery doesn't work either, but booting to an install USB works. fsck finds nothing wrong, no updates available after running chroot from install USB. Reinstalling is possible to do but the problem reoccurs when running upgrade (on a fresh system!).

I'm very thankful for any help you can provide.

EDIT: Running Ubuntu 18.04.2. I can't recall what version I have on my install USB but it's slightly older. GRUB calls the two different versions I can boot to Ubuntu, with Linux 4.18.0-20-generic and Ubuntu, with Linux 4.18.0-15-generic as well as recovery options for both versions. Currently, only Ubuntu, with Linux 4.18.0-15-generic (recovery mode) works.

Solution

Problem seems to be related to this bug https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1829620

One of the workarounds posted by Steve Beattie on this post helped me.

An alternative approach would be to add IUCODE_TOOL_INITRAMFS=no to /etc/default/intel-microcode and then re-running 'update-initramfs -u' to remove the microcode bits from the initramfs image. NOTE: you will want to remember that you did this so that you can re-enable microcode updates once this issue has been resolved.

I hope this can help others who find this question.

Comments

[guiverc]

What distro? You refer to any distro but provide no detail. You state 'running upgrade (on a fresh system!)' but again don't say what flavor or release.

[Per Edwardsson]

Running Ubuntu 18.04.2. I can't recall what version I have on my install USB but it's slightly older. GRUB calls the two different versions I can boot to "Ubuntu, with Linux 4.18.0-20-generic" and "Ubuntu, with Linux 4.18.0-15-generic".

[guiverc]

Tha is useful information, that should be added to your question (so many people read it). You highlight it occurs with specific kernels (ie. your hardware has issue with a kernel upgrade) and you want the most people to read it so they can help you (faster too). The version(s) you can't boot with, plus version(s) you gave that you can boot are useful, and not everyone reads comments, so you should edit & add additional information there (you can edit your own questions)

[Wipster]

I had the same problem with my Zenbook UX533FD and Elementary OS Juno. After updating the bios to version 304 it was fixed.

[filimonov]

That link saved my day.