I reported a bug on this issue and have had zero response
http://bugs.launchpad.net/ubuntu/+source/grub2-signed/+bug/1474342
The problem is that I can no longer turn on my laptop and expect it to boot. 3.19.0-20 was the last kernel to boot. After I did an update to 3.19.0-22 I could no longer boot and the only way to boot was to hit Esc, get the list of kernels and choose 3.19.0-20 or lower.
This morning I installed 3.19.0-23 and again it won't boot. The list of bad kernels has 3 bad kernels and is still growing. This is scary to say the least and I need a solution.
One solution might be to format my disk and start over. This is clearly painful as all programs which I have will be lost. There is also the problem that perhaps there really is something wrong with these kernels for my given laptop. (On this computer they obviously work fine or I couldn't write this message.)
Please look at the bug for more details, but I really would appreciate some serious help to get my laptop back on line like a "normal" computer.
Thanks,
Ilan
Best Answer
I too had the same problem and it had to do with BIOS settings.
The good news is that you do not need to worry about data loss. You can take a disk image with clonezilla:
http://clonezilla.org/
go into your BIOS and delete any unused boot managers, check your disk for errors and then see if the bug happens again. If it does, clone your disk and sanitize it, then re-install.
That is what worked for me. Of course you will want to ensure that your disk is working correctly and that your BIOS is correctly configured before you do anything...