[SOLVED] elilo broken on Slackware 14.2 after Windows 10 update on dual boot UEFI system

hyperhead · 08-03-2016, 03:35 AM

Hi,

I had Slackware 14.1 and Windows 10 (don't judge me) happily co-existing on dual boot UEFI for a year or so. However I got the bug to upgrade Slackware to 14.2 and Windows 10 recently.

Slackware 14.2 installation went fine and again both OS's could be booted via UEFI.

However after the Windows 10 Anniversary update I can no longer boot Slackware from the UEFI menu.

I have booted with my Slackware rescue USB disk and Slackware 14.2 boots ok. I run eliloconfig and re-install elilo, but still I cannot get Slackware to boot from the UEFI boot menu (there is content in /boot/efi/Slackware directory)

Has anybody got any troubleshooting tips here? After a previous Windows upgrade this happened and re-running eliloconfig worked just fine.

Thanks!

zlin50 · 08-03-2016, 07:14 AM

Hi,

just a guess: did your windows-update change bios-configuration?

Otherwise: please describe the problem more detailed.

hyperhead · 08-03-2016, 08:21 AM

Hi zlin50,

I been in the BIOS and have UEFI only, CMS Support for legacy

Secure Boot is disabled.

The UEFI boot menu Slackware has an entry but when I try it, it doesn't boot, screen just flashes and stays on the boot list

Its puzzling as Windows did this once before the re-running eliloconfig did the trick.

Plus the /boot/efi/ directory looks sane.

I guess its time to learn more about UEFI

Thanks!

dugan · 08-03-2016, 09:18 AM

When you're in Slackware, use efibootmgr to put the boot menu entry back. The Windows 10 updater removed it.

GazL · 08-03-2016, 12:58 PM

FWIW, I did the the Win 10 update last night and my UEFI bootmanager entry came through unscathed.

hyperhead · 08-03-2016, 01:45 PM

I fixed it, it was not the boot entry, that was always intact, something very strange happened...

So when the BIOS was in strict UEFI only the /boot/efi/EFI/ directory was read only when I booted Slackware via the USB rescue drive, then when I ran the eliloconfig it didnt give an error, but was unable to write anything or copy to the Slackware directory the initrd or vmlinuz. This became apparent by inspecting the elilo.conf file which did not contain any entries and the directory which had vmlinuz but no initrd.gz, so not surprising it was not booting.

When the BIOS was in UEFI / Legacy and I used the USB to boot the directory was RW, but eliloconfig refused to run because the /sys/firmware/efi directory was empty.

Code:

# If the system is not running under EFI, skip running this script:
if [ ! -d /sys/firmware/efi ]; then
  if [ "$T_PX" = "/" ]; then
    echo "ERROR:  System is not running under UEFI."
  fi
  exit
fi

I added the entries for the image, initrd and root disk into elilo.conf, but of course I had no initrd which I recreated with mkinitrd. Once this was done the system booted again.

So after the Windows 10 upgrade somehow the initrd.gz went missing and the UEFI BIOS entry may or may not have been set to strict

Anyhow, problems fixed. Thanks for the input.