Booting Lenovo T460s after Fedora 24 Updates

Introduction

I recently picked up a new Lenovo T460s work laptop. It is fairly light and has 20G of memory, which is great for running Virtual Machines. One of the first things I did on this new laptop was install Fedora 24 onto the system. After installing from the install media I was up and running and humming along.

Soon after installing I updated the system to get all bugfixes and security patches. I updated everything and rebooted and:

Probing EDD (edd=off to disable)... OK

Yep, the system wouldn't even boot. The GRUB menu would appear and you could select different entries, but the system would not boot.

The Problem

It was time to hit the internet. After some futile attempts on Google searches I decided to ask on Fedora's devel list. I got a quick response that led to two bug reports (1351943, 1353103) about the issue. It turns out that the newer kernel + microcode that we had updated to had some sort of incompatibility with the existing system firmware. According to the comments from 1353103 there was most likely an assumption the microcode was making that wasn't true.

The Solution

The TL;DR on the fix for this is that you need to update the BIOS on the T460s. I did this by going to the T460s support page (at the time of this writing the link is here) and downloading the ISO image with the BIOS update (n1cur06w.iso).

Now what was I going to do with an ISO image? The laptop doesn't have a cd-rom drive, so burning a cd wouldn't help us one bit. There is a helpful article about how to take this ISO image and update the BIOS.

Here are the steps that I took.

  • First, boot the laptop into the older kernel so you can actually get to a Linux environment.
  • Next, install the geteltorito software so that we can create an image to dd onto the USB key
$ sudo dnf install geteltorito 
  • Next use the software to create the image and write it to a flash drive. Note, /dev/sdg wsa the USB key on my system. Please be sure to change that to the device corresponding to your USB key.
$ geteltorito -o bios.img n1cur06w.iso 
Booting catalog starts at sector: 20 
Manufacturer of CD: NERO BURNING ROM
Image architecture: x86
Boot media type is: harddisk
El Torito image starts at sector 27 and has 47104 sector(s) of 512 Bytes

Image has been written to file "bios.img".

$
$ sudo dd if=bios.img of=/dev/sdg bs=1M
23+0 records in
23+0 records out
24117248 bytes (24 MB, 23 MiB) copied, 1.14576 s, 21.0 MB/s
  • Next, reboot the laptop.
  • After the Lenovo logo appears press ENTER.
  • Press F12 to make your laptop boot from something else than your HDD.
  • Select the USB stick.
  • Make sure your laptop has its power supply plugged in. (It will refuse to update otherwise.)
  • Follow the instructions.
  • Select number 2: Update system program
  • Once finished reboot the laptop and remove the USB key.

Done! I was now happily booting Fedora again. I hope this helps others who hit the same problem!

- Dusty

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