I have one suggestion for how to fix the problem.

Try using a traditional device node, instead of booting with the root
partition set as a UUID. The UUID may have changed over kernel upgrade.

Have a look in /etc/fstab to find the right device node for "/"

And edit your grub configuration line so that root=  points to that
device node.

e.g root=/dev/sda5

Where /dev/sda5 is your root partition. If that works to boot your new
kernel, change your grub configuration to that permanently. 

If you do need to use UUID's for some reason use the blkid command to
find out the correct UUID whilst booted to that kernel.

Let us know if that helps.