How to fix iPhone 4 front camera shutter lock?

I've got an iPhone 4 which I smashed and got repaired.

Unfortunately whilst being repaired the front camera has completely broke (it worked when it was shattered). If I select the front camera it'll lock the shutter and I can't access the camera without a third party app.

I've tried restoring from new and hard resetting but no joy. My device is a GSM model on 6.1.3 semi untethered jailbreak (my current workaround is disabling the front camera via iFile.

The video recorder is also slightly bugged and is zoomed in once opened, I have to zoom out which gives black edges on either side (the recorded video file isn't affected and is still in the right resolution)

It's clear it's a hardware issue so I'm wondering what to look for when I open up my device. Could a loose connector cause this problem? I've looked online and saw that a small part of the logic board is a huge possibility for the problem I'm having but how far do I have to dig inside my device to find that component?

I would send it to Apple and have them repair it.