I recently purchased a new camera module for my M7 hoping to fix the purple camera issue. Headsup, it didn't fix it. Opening up the phone wasn't all THAT hard. Granted it is harder than your galaxy S5 (that's what she said). but with a little bit of patience and the right tools, it can be done without damaging the phone.
So my issue now is, Wifi is technically working. the signal just sucks. And I haven't been able to pinpoint which spring contact leads to the back housing (which acts as an antenna). Any ideas?