Hey Guys,
I would like to post the solution for the camera problem, because I'm in the same boat.
Got a second hand lumia 1020, camera working with 8.0, not with 8.1 or 8.1 update (dev preview).
Cannot send in the phone to nokia support, because you need the bill or copy. Even the phone has a valid warranty.
Problem appearance: Under WP8.1 all camera apps automatically close after opening them, as well the HERE Maps app.
The problem is a combination in hardware and software:
-Software: in WP 8.1 they changed the camera api: on camera start both cameras will be checked (front and back).
-Hardware: The early Lumia 1020/920 phones have a hardware issue with the front camera.
How can you verify if it is a front camera hardware problem?
Downgrade to WP8.0 and start the nokia pro camera app, the 41MP camera image is working fine. Now switch to the front camera:
If the screen turns black, and nothing happens, then you have a faulty front camera. (Only a reboot will make the camera app work again, under WP8.0!)
If the front camera is working under WP8.0, my solution will probably not help you!
If your phone is still under warranty, send it to nokia! They will fix it. By replacing the front camera flex cable unit.
Otherwise, if you're not afraid to take apart your phone, you can buy a "Nokia Lumia 1020 Front camera" on e.g. ebay. (like I did)
Something to point out (I think): I watched out in the ebay offers, to see the back of the back of the flex cable, because there is a partnumber/version printed on. I would guess nokia did a rev. 2 on the front camera flex cable because the part from the new spare part was different (higher) that the rev. which was in my lumia phone.
How to take the Lumia 1020 apart? Please watch youtube teardowns or similar forum posts. It' easy.
But be gentle with the flex cables (display) and the connectors on the main board.
After changing my front camera (on flex cable with the proximity sensor), everything works fine!
Costs: 29 Euro for the front camera.
I attach some photos of the new/old front camera unit (optically no difference, only the part/version number differ)
Currently I'm running WP 8.1 Dev Preview in the latest version 8.10.14192.280 ("critical update") and the battery life increased from 1,5 to 3 days :amaze: I'm very happy
Greetings Alexander