Comment 23 for bug 1611277

The user-space tool that is responsible to set up fakeraid (except for Intel MSM and DDS style meta-data). Make sure that package is still installed and the dmraid command is still usable.

A rc1 mainline kernel is probably a bit too recent since the first release candidate can always be unstable. A 4.7 final maybe would have been better, though I suspect its less of a kernel issue than a problem with the user-space tool. Maybe related to the kernel because the interface to set up a device-mapper raid1 could have changed.

Not sure if you know how to get back to a working kernel. If not, it should be possible to quickly hit left-shift between BIOS and the hidden grub screen to get to the grub menu (though I am too slow most of the time). From there one would select the alternative option and there has the choice of older kernels.