Remember the original comes with aluminum tape wrapped around it. I always thought it was to protect it from external interference. I was half-right. It does protect it from external interference but it also protects the antennas from the digitizer's interference. I got some aluminum tape , wrapped it around the Digitizer's IC and et voila! We got a fix in 16 seconds from 14 satellites.
I also came up with a mod on the back plate.
What we did was , we cut 2 aluminum foils to 3-4 mm width and then starting from the gps contact zones which are located at the right corner of the back plate we started to lay them down avoiding other antennas as best as we can. We worked our way to the bottom with that foil and then connected that foil to the ends of an antenna sticker that we bought off ebay. Then we secured everything in place , and closed the device up. Another et voila , Fixes the position in 5-8 seconds on the same spot. This could theoretically work on the gsm/3g antenna as well although we haven'T tried that , we got pretty good reception where we live. I think those are also on the back plate.
Anyway folks , that's about it. I thought i'd share my experience with you guys so you don'T have to live through the same thing and even make it better. I wish i could provide some pictures but we closed the device up to test it and did not pry it open again. It gets really tense when you're prying open your only phone.
Note : Use copper foil if you can find that , it has better conductivity.
On top of all those , you need to ground your antennas on the designated places around the frame. Mine came with the pads although some assemblies apparently don't have those , i recently had one. The original has sponge pads to provide contact since those parts of the board are recessed a bit. So , the ground connections need elevation to make contact. Use conductive tape (stack 3-5 together that should be enough) to elevate the points. The ground point just below the front camera is responsible for grounding the gps antenna , i'll mark that in the picture.
The other pictures are there to point out other components. The reference one is the one with the blue tape all over it.
That blue tape insulates the the chips , especially the emmc from the frame. You also need to do the same. You don't want the frame to accumulate charge , because then it won't ground.
WARNING : CUT THE EXCESS TAPE TO THE SHAPE OF THE RECESSED GROUNDING POINT. DON'T SHORT ANYTHING OUT. ESPECIALLY THE ICs.
Thanks to Eriol The Mariner for bringing the grounding issue to my attention.