One doesn’t actually HAVE to remove the display. But it does make the removal of the battery easier, at it is very well glued to the back case.

When reassembling the iPhone 5c, I used the flat end of the spudger to press on the connectors and maintain them while replacing the front panel on the body of the iPhone.

The third and "deepest" connector no longer slips out of its socket, which it did before holding the whole lot with the spudger.

I would unplug the battery cable before removing/upgrading the RAM.

I've done this rear panel replacement on two iPhones, and each time I had the same problem:

The vibrator no longer spins / vibrates, although everything else works fine. The mute button also works fine: it does mute the iPhone, but no longer activates the vibrator.

I tried moving slightly the two little connectors on it's side (towards the dock) without any result.

Who would have an idea?

Those "6" and "7" antenna connectors are quite fragile.

Be very careful when assembling not to force the connector down; It should click actually quite easily once it's placed properly.

If you try to force the connection, it might easily be deformed, which would really be a pity.

NO!! Don't use glue as this little part which you fix with the screw is the SIM card extractor: it has to be able to move.

I used an IV needle to "drill" the hole. You may also use a big safety pin.

while reassembling, it's quite helpful to use a bit of tape (on the out side) to maintain the button

while reassembling, it's quite helpful to use a bit of tape (on the out side) to maintain the button

4 screws: If the 3.8mm (orange circle) is #1

#2 and #4 are identical

#3 has a smaller head.

Be very, very careful not to scratch, puncture, press, damage, deform… actually just DO NOT touch the battery units. They are extremely fragile.