I'm having the same sort of issue, I (stupidly) did an update thinking it wasn't a major update so wasn't an issue, now my N54L is stuck on 6.0.2-8451 (can't remember what Update # it was) in Recoverable.
Now I can access the partitions using gparted, but can't figure out a way to access the files to change the version number trick and all that. So figured, is it just easier to delete the /dev/sda1 /dev/sdb1 etc partitions and start again?
I was about to just do that but thought I'd better check on here to make sure it will definitely work and won't screw up my data.
EDIT: Went ahead and deleted all the system partitions, ends up that I can't just reinstall the DSM as it will wipe all my data. I have a backup from about 2 months ago so won't lose too much data, but still a pain in the arse.
EDIT2: So after it warned that, all my data is actually still there. Happy days!