Locking and testing do not go hand in hand.
I suggest you get out of the testing channel without locking straight away. Not to be too harsh; testing is for those who know the risks without guidance at this forum level.
We know that the 3.1 build was held for further development but we don’t know the underlying issue. Further FP6 has fundamental build issues (related to it being a very new device) which may change for production.
Now wait patiently and hope that the “production” 3.x.x build arrives without incident.
Should the System Updater fail for any reason, you can then just “new install”.
- (Please bear in mind that I have broken the rules by even answering you regarding a release candidate)