Hi everyone!
I've broken my Z3C back glass and lower speaker. Got spare parts from eBay, then replaced it following your instructions.
As I've fixed many iPhones and other phones I consider myself experienced in it and this replacement was one of the easiest ones.
Anyways, after putting everything together I started it up and the display was a bit dimmed in the right bottom corner and blinks when I push the back glass. Even just a slight force is enough for it to blink.
Can't find any relevant answers on the net, so I am turning to you with this Q.
Thanks everybody a lot for the tips!