Solved/Deleted - seems the problem was the update used too much disk space. After deleting some files, sparky started again.
At what point of booting into SparkyLinux did you get stuck? Also, what version of Sparky are you using, semirolling or stable? I'm guilty of omitting this myself. More information is still useful.
I don't have any solutions or explanations for you, however, I am as curious about the problem you experiences as I'm sure others may also be. More information would still be very useful even though your problem is thankfully [Solved]!
Good job!