@PeterGuru: the flashable firmware zip is the least work as it only contains the firmware for current bacon LP custom roms and only needs to be flashed once, it does not touch any of your existing rom(s) partitions and right after reboot your rom should boot up without loops. Flashing a full CM12 nightly entails all the work of wiping it again just to restore your nandroid all over, which is not necessary.
However, judging from your signature's radio version, you seem to have at least once flashed a CM12 nightly?
P.S. totally dig your signature quote!
On everything else, now I'm even more confused.
I've been using CM12 since it came out a couple of weeks ago. The nightlies flash perfectly well each day. However, when I do a Nandroid, which I perform once a day, it appears to be successful because TWRP tells me it's successful. Nonetheless, I tried to restore the latest Nandroid this morning, and I got the loop. I then tried to restore several other Nandroids, all CM12, and all caused the loop. By the way, whenever I restore a Nandroid, I always completely wipe my system (except internal storage), so that the Nandroid can restore on a clean device. In the past, with every other phone I've had, the restore went perfectly well, and it was simple. This time, though, nothing! Just the continual loop from the OnePlus first screen and then back to TWRP.
I've done this 1000s of times, but now I'm at a complete loss as to what's happening. Obviously the Nandroid is NOT successfully re-installing even though I get a SUCCESS notification in TWRP after the restore is complete. It's when I then try to reboot the system when the loops begin.
So, as it stands, it's impossible for me to restore any Nandroid, so what's the use?
I also tried flashing your firmware after the complete wipe and BEFORE the restore process. I also tried flashing your firmware after the restore. Nothing helped. I then tried flashing the latest CM12 nightly, the one that was working prior to this entire mess, and then performing the restore, and the same problem happened. I also tried flashing the latest CM12 nightly AFTER the restore process and, again, the same loop issue. Basically, I've tried everything I can think of, with no success.
Now I've wiped the system, for about the 10th time this morning, and JUST reinstalled the latest CM12 nightly and GAPPS. My phone is back up and running again, but now I have to spend about 4-6 hours to not just re-install all my apps, but to then go into each one and set them up properly. It's a frustrating and pain-staking procedure.
Restoring Nandroids via recovery is really the most important function of any recovery, and it's simply not working with TWRP 184.108.40.206.