I accidentally broke the ribbon cable in the upper left that dives under the blue daughterboard. I'm not sure how, but it was probably trying to get the tape loose. The only problem it seems to have caused is that the proximity sensor (next to the front-facing camera) doesn't work and neither does the notification LED.

During the reassembly, I noticed something that I'm not sure if it was an issue or not. One of the ribbon cables in the upper left appears to tuck under the blue board. You can see this in Step 12. When I reattached it, I noticed this piece of cable was loose and no longer tucked under and it didn't appear that it was supposed to connect to anything because I didn't see any contacts, but I couldn't figure out why it was there or if it had somehow broken loose. The phone is working OK including the volume buttons with the exception of the Light/Proximity Sensor and NOtification LED. Neither of those are working so I'm wondering if this ribbon was supposed to go to them.

I ordered one from BinTek mobile and it seems to be working well.