I might be mistaken...I thought there was a problem with the first or second iteration of our software, where if you unlocked the bootloader it broke the camera. I can't find a link right at the moment and I may be thinking of the Z Ultra rather than the Z Ultra GPE (if there's a difference) I'll dig around a bit and see if I can't find it after work today..
My camera worked on an unlocked bootloader on 4.4.2. It didn't break until the 4,4,3 update