[TG01 ROM Development] kevinpwhite:
Probable GPS Issue Resolution....

You're quite right ! The illogicality has been bothering me considerably:confused:. Hoever, this morning's events have shone some possible light on the matter::)

Status last night - both TG01s running happily side by side; one with the basic hybrid IT .tw + UK payload, the other with the stock UK.

This morning - neither would lock on to the satellites. The hybrid tried feebly a couple of times and then went into the 'looking for GPS' routine the same as I'd been getting with previous failures.

This pointed towards a receiver issue rather than the ROM. Took both outdoors to clear sky and still coudn't get anything. So SR'd both and restarted the GPS in each. Took about 3 minutes, but then obtained strong lock on both and able to move them indoors to previous test position.

Using the Hybrid as a control, have then fresh DL'd the 0.001 debranded ROM and reflashed the other device with that. Again taken outdoors to initiate satellite lock and moved in to previous test location.

0.001 has now been running with a solid 3D lock for about 4 hours. Updated @14:30

Now repeating with the 0.009 version alongside; good lock obtained outdoors and now transferred to test position alongside the running .001.

0.009 has now been running with a solid 3D lock (apart from just 2 dropouts/quick reconnections) for about 2 hours. Updated @14:30

So, after all that, it appears that in all probability there is no issue with the ROMs; rather with the vagaries of the GPS receiver obtaining an intial signal lock....

Next Steps

- I will update later, following above....

- If situation remains the same, then will try a locally modified ROM and check for consistency.

Update 9 April

- I think is now definitely confirmed that there was in fact NO ISSUE with the ROMs with respect to GPS operation, although at the time of testing the indications were certainly suggesting that.

- I have since done further trials and also built a couple of separate ROMs (derived from Arag0n85's originals) with further items removed / registry edits applied. These work fine too.

- What I now believe is that there is a significance to the initial lock obtained by the receiver when using Garmin XT; it also makes a big difference if the clock in the device is set correctly and if the initial Location is set. This evidently impacts the capability of the device to 'find' itself through reference to the built-in almanac it uses to establsih the correct set of satellites which should be in view depending on Date, Time and Location. This is very relevant if testing without a SIM card in place and consequently the device not having access to the AGPS data to help initialise location. In early tests (when the main 'issue' appeared to be cropping up, pointing to the ROMs) I have now realised that one device had a SIM in, the other didn't. Moral - ensure any side-by-side trial is truly on a like for like basis !

So, to conclude the saga - a bit wiser and hopefully some of the information now identified will be of wider use; and last but not least, my apologies to Arag0n85 for a lot of unecessary (as it turns out) head-scratching over the ROMs.