No bootable disk after upgrade from 14.04 to 14.10

[phb]

I had a working Kubuntu 14.04 on my fairly modern laptop with secure boot disabled and CSM enabled. Upgrading to 14.10 left me with a non-functional box complaining that there are no bootable disks. Re-installing from scratch produced the same result, so I suspect that the installer has made some deductions about UEFI and screwed up grub. The ISO DVD boots just fine so I'm fairly sure I can recover with a little chrooting and grub-install, but it would be good to identify the problem, not just for me, but others with perhaps less computer experience.

Anyone with any thoughts/ideas?

Thanks in advance. Peter HB

[phb]

Problem resolved by trial and error. It looks like a bug in the installation process(es) as non-secure boot only works if the EFI partition is deleted and secure boot doesn't work even with the EFI partition enabled. Non of this would be a great issue with a fresh install, but I'm fairly sure that a distribution upgrade shouldn't leave an un-bootable system!

[SteveRiley]

Hm... can't say that I experienced the same thing here. I have a ThinkPad T520 with UEFI. The EFI system partition is /dev/sda1. Secure Boot is disabled. I don't use GRUB; intead, I use rEFInd.

When the time came, I upgraded using sudo do-release-upgrade -d. The upgrade proceeded as normal. It also installed GRUB and placed GRUB's EFI boot loader in my EFI system partition. I simply purged all GRUB packages and the left-over bits in the EFI system partition. rEFInd was untouched during this process.