From the iFixit breakdown I found the attached image, this circle cutout seems to line up with where I see a slight yellow tint on my screen.
The logic board with a chip sits right behind this hole.
Step 14
http://www.ifixit.com/Teardown/iPhone-4-Teardown/3130/2
Just thought if it's heat related.
The logic board with a chip sits right behind this hole.
Step 14
http://www.ifixit.com/Teardown/iPhone-4-Teardown/3130/2
Just thought if it's heat related.