Comment 12 for bug 1384973

In my setup, Asus Vivo PC vc60 dual boot with Windows 8.1, I have met this problem since I upgraded kubuntu from 14.04 to 15.04. Today I have tried to play with shim package and UEFI settings, finally I got rid of the message. I have done a lot of things, so this protocol might be redundant or wrong in some part, but you can try if you wish so. Uninstalling shim doesn't change anything in the boot message. so I went to UEFI options:
- Changing the UEFI settings seems to work in this way: Secure Boot -> Windows UEFI enabled + Key Management -> Clear secure boot keys
- Pay attention that the UEFI chooses the right boot loader order in Boot option priorities: there are two options to boot Ubuntu (they are grub related options) and I have experimented both, plus some options to boot directly into Windows (I suppose you are not considering these).
- I reinstalled shim and updated grub, after that no more insecure Boot message.
System can boot in kubuntu (my custom packaged 4.0.4 kernel and the 3.19.0 stock kernel) and in W8.1 without warnings and wasting time.