Yes I guarantee that you can downgrade from Official OTA to RC29. Like I said I did it yesterday morning with no problem. I have used that same .nbh file since I started rooting RC30. Did you try using the one I posted?
T-Mobile HTC One successor to my T-Mobile Sensation 4g Successor to my TBD HD2 Successor to my EnergyRom TP2
OS: Elegancia™ v15.0 | Sense 5 | HUB-APM-hEQS-OTA | 3.22.1540.1 | JB 4.3 |
and don't forget to thank me if I have assisted you in any way