i don't know enough about software coding to say this with any authority but as i posted earlier, the Tmobile USA UNOFFICIAL leaked firmware worked so well for me i'm ecstatic - over a 9 mile circuitous route, all secondary roads, speeds mainly in the 30-35 range with some in the 55 range, about 25-30 turns (this drive was expressly to test the firmware), there was only one anomaly and the more i think about it, it may well have been the MyTracks program - but when i first left the house, the track showed me exactly where i was at the end of the driveway on the left corner of my lot. When i turned onto the road, at the far side of the lot (155') it showed me exactly where i was. Then about 1/4 mile down at the corner it showed me exactly at the stop sign, literally. Then i turned - the anomaly that showed up later, the track showed me turning right about 10' before the corner as if i was clipping across my neighbor's lawn. But the rest of the track was spot on - on the 4 lane roads, it showed me in the exact lane i was in, when i turned left, it showed me having gone down the left hand turn storage lane.
when i pulled into a gas station (under a huge metal canopy) to get gas, i did a 180 degree half circle coming out from under that canopy and it located it accurately.
when i got home i forgot to turn the mytrack log off and walked out into the yard to pick up some limbs that had fallen down - the track included that foot path.
the part that i can't state with any authority - the folks that seem to have some problems still - are all or seem to be folks that have flashed the bejesus out of their phones (one actually stating that he re-flashed someone's 'gps fix" overtop the leaked firmware. i have to wonder if all the flashing they've done has left some remnants of earlier flashings on their phones - - i can't state that like moses with the tablets on the mountain, but before the flash my phone would not lock on 2-3 sats max outside, maybe 1-2 inside but the accuracy at the last test was something like 1600 feet - with this flash, it is dead on. With the flash, inside viewing 10-11 sats and locking on 3, 4 or maybe 5. Outside - viewing 12 sats and locking on 7-8 (or more).
the ironic part was i just sent my vibrant back (for some other issues) but i tested it again yesterday before packaging it and it was still dead on.
FWIW - if i re-purchase the phone, where i was cynical about sammy actuallly fixing or or being able to, i'm now a helluva lot more comfortable if it's not totally fixed, it's damn close.
