[Xperia Z2 General] unni_kmr:
I thought I would share my experiences / lessons learned while I tried to replace my Z2's (D6503) back panel and battery.

Recently, the back panel started coming off on its own. I thought it was because of weakened adhesive. So, I ordered a back panel from Witrigs along with the adhesive (part 1 & 2, links below). I also got a guitar pick (part 3), suction mount (part 4) and a spudger (part 5) from Witrigs. It took about 3 weeks to get the parts.

Before removing the panel, I watched these videos: video 1, video 2.

I used a heat gun that I borrowed from work. Looks like a hair drier will also work. In video 2, you can see that the panel breaks when he was removing it. I think he didn't heat it enough. I used the heat gun for around 1 minute. The phone became really (almost unbearably) hot to touch. Then I slid in the pick and the panel came out easily in probably 2 minutes. The difficult part was in removing the glue residue. I spent almost 30 minutes doing that. I also used a alcohol hand sanitizer and cotton swabs for cleaning the glue residue. I am not exactly sure if the hand sanitizer helped or not.

Then I applied the panel and adhesive. Unfortunately, the adhesive didn't stick. I realized its because the battery was pushing the panel. The battery had expanded on both sides (the outer cover was bloated). So, I ordered a battery from Amazon (part 6). Since Witrigs was taking time to deliver, I also ordered the adhesive from Amazon (part 7). Both arrived in less than 5 days. I cleaned the original cover, put the new adhesive and battery and it fitted properly. But now there was a new problem. Camera became very blurred. Before putting in the panel this time, I had run the cotton swab on the camera glass on the panel (inside and outside). I didn't touch the actual camera lens. I don't know if that caused the blurriness or if it was the heat from the gun, the blurriness is not going away. I tried rubbing toothpaste (someone recommended it in XDA), that didn't help either. The panel I got from Witrigs didn't have any blurriness. Unfortunately, while trying to remove the adhesive residue from it, I scratched the black paint on the inside. Now if you place it in front of light, you can see the other side (its a very small scratch, but I also messed up another part mentioned later). This made me think if the Witrigs one was fake, but same thing happened to the original one a few minutes later. So, while cleaning the residue, don't put too much pressure and don't use anything sharp.

Another thing I learned was not to direct the heat gun on the inside of the panel. I did that with the Witrigs one while trying to remove the adhesive residue. There is a plastic part that sits in front of the flash LED. The heat caused part of it to melt.

So, now I have ordered a new set of panels, NFC and adhesive from EPartsSupply (parts 8, 9 & 10) since Witrigs is out of stock. Waiting for them to be delivered.

Also, before putting the panel in, make sure that the phone turns on (to ensure that the battery connector is properly in place). Also make sure that plastic part in front of the flash LED is in there. Its glued to the panel, but not that hard to remove. So it may accidentally come off.

Parts Used

Note: Please don't blindly buy these just because I listed them here. Chances are they may turn bad after a few weeks. I am particularly concerned about the battery and whether the adhesive will hold.

Part 1: Back panel from Witrigs

See attachments Back Panel - Inside/Outside.jpg. The one on the left is original.

I couldn't feel any physical difference between the original and the Witrigs one. I am not sure if the glass has the same property as the original.

It also comes with NFC and the adhesive. You just need to peel of the cover and place it on the phone.

Part 2: Adhesive from Witrigs

Part 3: Guitar pick

Part 4: Suction mount

Part 5: Spudger

Part 6: Z2 replacement battery

See attachments Battery Front/Back.jpg. The one on the bottom is the original.

The new one looked identical. I couldn't say for sure if it was fake. I will use it for a few days and see if I notice any difference and update here.

Part 7: Adhesive from Amazon

I am not sure how long these will hold. I recommend getting at least 2 adhesives because you may not be able to align it properly the first time. The method I have adopted is this:

Remove the protective covering meant for the panel side.

Align the tape on the phone carefully (note that the phone side cover is still present)

Place the panel on the tape and push it in.

Lift the panel. Remove the phone side protective covering.

Push the panel in.

Apply heat for a few seconds on all sides. (Note: I am not sure if this will strengthen the bond). Push firmly.

Part 8: EPartsSupply back panel

This doesn't have NFC.

Part 9: EPartsSupply NFC antenna

Based on video 1, it looks like its possible to remove the NFC antenna from original panel. When I tried to remove it from the Witrigs one, I ended up tearing it. So, I don't want to take a chance.

Part 10: EPartsSupply adhesive