Ok, i'm maybe gonna chuck '[Only registered and activated users can see links. Click Here To Register...]'. My habit of making outrageous statements might be irritating to some ppl but i believe we need to be openly polarized about this 'problem', i.e. I think there are 3 main camps:
(1) those who think there is no real problem and therefore nothing needs to be done about it;
(2) at the opposite end are those who not only believe that the accuracy problem is real but who passionately seek a solution;
(3) in the middle are those who find this investigation interesting and are participating mostly out of interest and curiosity.
I started in Camp 1 as evidenced by my statement in post #6 linked above. I've now moved to Camp 3. I may be one of the few users here who have used GPS (i) on road in cars, heavy trucks & on bikes; (ii) outdoors both day and night [in military situations on foot navigating in difficult terrain]; and (iii) in aviation. I can state categorically right here and now that automotive use on road does not require the same degree of horizontal or vertical accuracy as the other two. Normal auto use particularly does not need highly accurate vertical readings, as evidenced by the fact that nobody except me has commented on the wildly varying altitude readings between the converted and unconverted units. Have a look at the readings. They generally don't agree. Maybe none are correct, i haven't checked but that's not my point. It's that the divergence is much wider than their horizontal 2 D divergence and i believe that is perhaps to do with hotfix probably not geared to work on altitude, only on coordinates. None of these unit rely on SBAS (WAAS) or LAAS or any other physical (real) means of positional error correcting. What they have is software help with that, e.g. lock on road, hotfix.
To some degree i think this is a 'storm in a teacup'. Nobody is going to die in a fiery plane crash because he used his 37>34 convert to make a rainy/foggy/night landing approach only to find out too late that he was 50' to the right/left of the centreline and/or 100' lower than he thought. Nor die because he accidentally stumbled onto an enemy firepit during a nighttime recce intending to set up an ambush or sniper post. Where such close accuracy is important there are specialized precision gps units designed for those jobs. I'm not being dramatic here, just trying to put this in context and perspective. So i believe this absolutely: Vertical (3D) precision is of little importance for auto devices and 15 metre/50 feet 2D accuracy is good enough. No doubt others hold a difference view and i'm not saying they are being precious about wanting 3 metre/10 feet 2D accuracy in an auto device. But if you do want it, and kunix cannot sort this out with a fw mod, then convert back to 3790.
Regardless, i'll do a side-by-side of virgin and convert in the city when i can. If kunix has come up with some new tweak i'll test that too. If not, i'll revert the 3490_kunix to regular 37>34 convert and include that just in case it's different gps hw to the others [as kunix said, maybe his mod didn't actually flash anything]. I only wish i knew someone locally with an original 3490 too. God know's dasivarsa won't send his over to me. ;)
PS: Angelo, do you wanna buy my 3590? Make me an offer. I must say i'm a little surprised that the smaller-cased 3790 is more accurate than it.