Help GPS fix S5 - Dummies Guide

[ironass]

One of the features of the Samsung Galaxy S5 phone that I use a lot is GPS and Google Maps. Both for work and play. In fact, I've been using phone based GPS since my Nokia N80 days, some 9 years ago.

The S5 can pick up satellites very quickly and offers me a fix of within 5m, (16ft), in around 20 sec's or so on a clear day, outdoors in the garden at home.

In fact, so good is the S5 with GPS that I have abandoned using dedicated GPS equipment.

In my own home the GPS can even detect the part of the house I am in with a slightly longer fix time.

For anyone who is experiencing GPS location and/or fix time problems, there are a couple of things that you can do which may help... although it will not fix a broken/damaged GPS antenna or improve your GPS if your government offers a degraded or non existent service.

#1. On your phone go to Settings > Location > Mode > High accuracy is set to ON. I find that this setting has no discernible impact on my battery life. Using Power saving or GPS only will greatly degrade the accuracy and increase, considerably, the time for a fix. Then go to Settings > Wi-Fi and turn it on. I leave Wi-Fi enabled 24/7 as, once more, it has no discernible impact on my battery life, (I do, however, have Always allow scanning, unchecked in Advanced).

#2. Download GPS Status & Toolbox, free from the Play Store. There is a paid version but the free one will suffice. However, supporting the dev with the paid version is good.

#3. In GPS Status & Toolbox, go to Menu > Settings > GPS & Sensors > Auto-download AGPS data and choose how often you wish AGPS, (Assisted GPS), to be updated. I use once a day as it is only a few bytes of information. You may decide more or less. Also Sensor filtering. I have mine set to weak but you can experiment. A stronger sensor filter increases the GPS fix time a bit. Also, under Menu > Settings > Display & Tools > Keep the screen on... check this as you will need to see your screen in step #7.

#4. Other settings you can choose to suit yourself and your location, such as meters/feet, miles/kilometers, etc: Unrooted users can now go to #6

#5. For rooted users up to Android 4.3 only. (Not necessary) Download TopNTP, free from the Play Store and select your location. This now tells your GPS to use a local location service which can speed up your fix time. You can also try their suggested NTP service but I find that the local one is quicker/more accurate for me. (N.B. May not work on Lollipop or Marshmallow)

#6. Now take your phone outside, away from buildings if possible and with a clear view of the sky. Open GPS Status & Tools > Spanner icon (you can touch a blank area of the screen to bring this up) and select both Compass calibration and Calibrate pitch and roll and follow the instructions for calibration.

#7. Now, still outdoors, put your phone into Flight Mode so that the phone is only using its internal GPS for a fix and go to the aforementioned Spanner icon > Manage A-GPS state > Reset and then leave it for around 5-10 minutes on a flat surface or until you see on the screen... Error 10ft (or 3m). This is about as good as it gets and may vary depending on your location.

#8. Now, very carefully without moving the phone turn Flight Mode off and in Spanner icon > Manage A-GPS state > select Download and then exit GPS Status & Tools.

#9. Now either, rotate the phone a couple of times through its three axis or do some figures of 8's with the phone.

#10. Go to Google Maps in Satellite mode and see how quickly you get a reasonably accurate fix. Don't forget, you can zoom in on Google Maps to see how close you are by placing two fingers on the screen and moving them apart.

Because I am a heavy GPS user, I tend to do items #6 -> #8 once every month or two but for most peoples uses, once every three or four months should suffice, if that.

Since all the apps I have mentioned are free, you have nothing to lose by trying it. Hope it helps!

TOP TIP: You might also like to try Here Maps by Nokia, free from the Play Store, which allows you to download a state/country/continent/world maps and voice directions in advance to be stored on your SD card thus saving you data downloads by using the off-line mode.

See, also...
35 Galaxy S5 models - know yours???
Lollipop Update Problems - Dummies Guide
Galaxy S5, Fake Clone or Genuine - Dummies Guide


E&OE This guide is written solely for, and on behalf of, Android Forums and may not be reproduced, in part or whole, without permission.

 

[ironass]

Right... pub!

 

[AZgl1500]

I will 2nd the motion of GPS Status and Toolbox.

I work the highways in summer months and need to accurately report problems involving Public Safety.

Before I take a picture, or use a map, I invoke GPS Status first.
Why? because it immediately interrogates a server to get the latest ephemeris which allows the phone's internal GPS receiver to lock onto the satellites in about 2 or 3 seconds. The 1st lock give errors of 9 meters or less, in another 2 or 3 seconds, it is down to 3 meters or less.

The S5 has the best GPS receiver I have experienced, much better than any of the Garmin GPS units in my cars, and I own 5 models of those.

I have CoPilot GPS loaded, and the entire USA maps loaded onto the extSDcard. When I bring up the CoPilot icon, it immediately shows me my current location to within 15 feet of where I am standing. You just can't get any better than that, well, the military can.... but....

I love their Paid version, it gives me turn by turn instructions with the phone's screen locked and in my pocket. great for my motorcycle rides.

 

[rizzer]

What does this app do to enhance gps, sorry I am a little confused about that

 

[ironass]

What does this app do to enhance gps, sorry I am a little confused about that

It downloads A-GPS data regularly, (set by user as per #3), and uses sensor filtering for faster, more accurate, fixes. For more info, see GPS User Guide and GPS FAQ

 

[EarlyMon]

It downloads A-GPS data regularly, (set by user as per #3), and uses sensor filtering for faster, more accurate, fixes. For more info, see GPS User Guide and GPS FAQ

Also a fast path to sensor calibration, something that is too often overlooked when facing GPS issues.

 

[mediaseth]

I'm confused. If the problem is solved easily through 3rd party software, why doesn't Samsung issue an update to fix it? I'm happy to try these out as soon as I get the chance (after work) and I appreciate all your responses. I just can't help but think that if it's this easy, shouldn't my phone already come with it? Why would a top tier phone like a Galaxy s6 not take proper advantage of its GPS hardware? EDIT - meant to post this in a different thread.

 

[ironass]

I'm confused. If the problem is solved easily through 3rd party software, why doesn't Samsung issue an update to fix it? I'm happy to try these out as soon as I get the chance (after work) and I appreciate all your responses. I just can't help but think that if it's this easy, shouldn't my phone already come with it? Why would a top tier phone like a Galaxy s6 not take proper advantage of its GPS hardware? EDIT - meant to post this in a different thread.

You misunderstand the use of the word, "Fix", in the title. In this context it is used to describe ascertaining your location as opposed to mending something that is broken.

 

[mediaseth]

Sorry- I was sent a link to this thread as solution to the GPS reception issues I'm having with the s6. I was able to drive from north of Boston to Providence RI without once getting GPS reception. This morning on my way to work, GPS reception would kick in and out. It happens whether I use Waze or Google Maps. AT&T changed my sim (WHY?) and sent me to the Samsung rep at Best Buy, who ran a bunch of tests, reset my phone's alarm without telling me ( ) and asked me to go back to AT&T if it didn't do the trick. I'm in these forums because I get red tape, otherwise. I'm very close to trying to make an insurance claim. I will need a different phone if I can't get GPS to work consistently, as it had with all my phones prior, including older Galaxy models.

 

[Big Gav]

One of the features of the Samsung Galaxy S5 phone that I use a lot is GPS and Google Maps. Both for work and play. In fact, I've been using phone based GPS since my Nokia N80 days, some 9 years ago.

The S5 can pick up satellites very quickly and offers me a fix of within 5m, (16ft), in around 20 sec's or so on a clear day, outdoors in the garden at home.

In fact, so good is the S5 with GPS that I have abandoned using dedicated GPS equipment.

In my own home the GPS can even detect the part of the house I am in with a slightly longer fix time.

For anyone who is experiencing GPS location and/or fix time problems, there are a couple of things that you can do which may help... although it will not fix a broken/damaged GPS antenna or improve your GPS if your government offers a degraded or non existent service.

#1. On your phone go to Settings > Location > Mode > High accuracy is set to ON. I find that this setting has no discernible impact on my battery life. Using Power saving or GPS only will greatly degrade the accuracy and increase, considerably, the time for a fix. Then go to Settings > Wi-Fi and turn it on. I leave Wi-Fi enabled 24/7 as, once more, it has no discernible impact on my battery life, (I do, however, have Always allow scanning, unchecked in Advanced).

#2. Download GPS Status & Toolbox, free from the Play Store. There is a paid version but the free one will suffice. However, supporting the dev with the paid version is good.

#3. In GPS Status & Toolbox, go to Menu > Settings > GPS & Sensors > Auto-download AGPS data and choose how often you wish AGPS, (Assisted GPS), to be updated. I use once a day as it is only a few bytes of information. You may decide more or less. Also Sensor filtering. I have mine set to weak but you can experiment. A stronger sensor filter increases the GPS fix time a bit. Also, under Menu > Settings > Display & Tools > Keep the screen on... check this as you will need to see your screen in step #7.

#4. Other settings you can choose to suit yourself and your location, such as meters/feet, miles/kilometers, etc: Unrooted users can now go to #6

#5. For rooted users only. (Not necessary) Download TopNTP, free from the Play Store and select your location. This now tells your GPS to use a local location service which can speed up your fix time. You can also try their suggested NTP service but I find that the local one is quicker/more accurate for me. (N.B. May not work on Lollipop or Marshmallow)

#6. Now take your phone outside, away from buildings if possible and with a clear view of the sky. Open GPS Status & Tools > Spanner icon (you can touch a blank area of the screen to bring this up) and select both Compass calibration and Calibrate pitch and roll and follow the instructions for calibration.

#7. Now, still outdoors, put your phone into Flight Mode so that the phone is only using its internal GPS for a fix and go to the aforementioned Spanner icon > Manage A-GPS state > Reset and then leave it for around 5-10 minutes on a flat surface or until you see on the screen... Error 10ft (or 3m). This is about as good as it gets and may vary depending on your location.

#8. Now, very carefully without moving the phone turn Flight Mode off and in Spanner icon > Manage A-GPS state > select Download and then exit GPS Status & Tools.

#9. Now either, rotate the phone a couple of times through its three axis or do some figures of 8's with the phone.

#10. Go to Google Maps in Satellite mode and see how quickly you get a reasonably accurate fix. Don't forget, you can zoom in on Google Maps to see how close you are by placing two fingers on the screen and moving them apart.

Because I am a heavy GPS user, I tend to do items #6 -> #8 once every month or two but for most peoples uses, once every three or four months should suffice, if that.

Since all the apps I have mentioned are free, you have nothing to lose by trying it. Hope it helps!

TOP TIP: You might also like to try Here Maps by Nokia, free from the Play Store, which allows you to download a state/country/continent/world maps and voice directions in advance to be stored on your SD card thus saving you data downloads by using the off-line mode.

See, also...
35 Galaxy S5 models - know yours???
Lollipop Update Problems - Dummies Guide
Galaxy S5, Fake Clone or Genuine - Dummies Guide


E&OE This guide is written solely for, and on behalf of, Android Forums and may not be reproduced, in part or whole, without permission.

 

[Big Gav]

Thanks ironass,
I only got into this cos I use the compass for work, Wase in the car and star charts when I gaze wonderingly at the night sky. I am surprised that any smart phone covers have a magnetic clasp if they interfere with the GPS so much - nobody else seems bothered that North is not where they expected! If you haven't followed this thread, the advice is get rid of the magnetic clasp and recalibrate your magnetic sensor - for most Samsung phones do *#*0*# Sensor - look at magnetic sensor and calibrate by a figure of 8 or move the phone through 3 planes. (Press back twice quickly to escape.) That aught to do it.

 

[gligeti]

Strange behavior on my G800F with TMH (T-Mobile Hungary)

I always had sort of crappy GPS, while it works perfect in my older car, it has issues in the newer, probably due to its windshield coating. It would lose the lock, or be too inaccurate for driving. I was sort of living with that assuming this is just what the phone can do, but strangely when the update to Lollipop came out (5.0.1 or as I recall) suddenly my GPS was robust in that car and kept the lock and never mislocated me even between buildings -- so I became hooked on Waze. But then when 5.1.1 came out, it broke again -- it seems worse than with KitKat.

I checked the antenna, and I don't think it is an antenna issue in my case (pushing that side of the phone does not improve the signal. Adding a copper wire has minor improvement, but not enough to make the fix stable in that car. Touching it with a large metal screwdriver or scissors makes a bigger improvement, but I can't make it a permanent fix.... Moving it to different locations on the dashboard makes no discernible difference either. The phone otherwise -- outside or in the other car -- gets a lock on 10-12 sats in decent time out of 18-23 visible with many being >30-35, usually 6-12m accuracy, which is not great, but works fine in the older car for navigation).

So while the general weakness of the G5 mini's GPS and the windshield is part of the issue there has to be a software part too since 5.0.1 was able to make it work with the same hardware and environment. Performing this ritual above doesn't help (like all other voodoo like wipe cache, limiting background processes, speed up animation, etc.)

I also noticed that while the other galaxy phones in the family would show all satellites (grey with 0 signal) that are in view once the a-gps data is downloaded before the fix, this S5 mini DOES NOT, only after it connects to the satellites. (I honestly cannot tell if it did when it worked well with 5.0.1. I was not staring at GPS toolbox or GPS test, I was just happily using GPS). I have a feeling that there is some sort of an AGPS issue, possibly with gps.conf that came with the firmware?

I did not want to root the phone, but if fixing the gps.conf would solve the issue I'd do it.

LMY47X.G800FXXU1BPC4
G800FXXU1BOL1
TMH

APN has default,supl

gps.conf says (since it is not rooted, I can only read it):

NTP_SERVER=north-america.pool.ntp.org
XTRA_SERVER_1=http://gllto1.glpals.com/4day/v3/latest/lto2.dat
XTRA_SERVER_2=http://gllto2.glpals.com/4day/v3/latest/lto2.dat
SUPL_HOST=supl.google.com
SUPL_PORT=7275

 

[ironass]

Strange behavior on my G800F with TMH (T-Mobile Hungary)

I always had sort of crappy GPS, while it works perfect in my older car, it has issues in the newer, probably due to its windshield coating. It would lose the lock, or be too inaccurate for driving. I was sort of living with that assuming this is just what the phone can do, but strangely when the update to Lollipop came out (5.0.1 or as I recall) suddenly my GPS was robust in that car and kept the lock and never mislocated me even between buildings -- so I became hooked on Waze. But then when 5.1.1 came out, it broke again -- it seems worse than with KitKat.

I checked the antenna, and I don't think it is an antenna issue in my case (pushing that side of the phone does not improve the signal. Adding a copper wire has minor improvement, but not enough to make the fix stable in that car. Touching it with a large metal screwdriver or scissors makes a bigger improvement, but I can't make it a permanent fix.... Moving it to different locations on the dashboard makes no discernible difference either. The phone otherwise -- outside or in the other car -- gets a lock on 10-12 sats in decent time out of 18-23 visible with many being >30-35, usually 6-12m accuracy, which is not great, but works fine in the older car for navigation).

So while the general weakness of the G5 mini's GPS and the windshield is part of the issue there has to be a software part too since 5.0.1 was able to make it work with the same hardware and environment. Performing this ritual above doesn't help (like all other voodoo like wipe cache, limiting background processes, speed up animation, etc.)

I also noticed that while the other galaxy phones in the family would show all satellites (grey with 0 signal) that are in view once the a-gps data is downloaded before the fix, this S5 mini DOES NOT, only after it connects to the satellites. (I honestly cannot tell if it did when it worked well with 5.0.1. I was not staring at GPS toolbox or GPS test, I was just happily using GPS). I have a feeling that there is some sort of an AGPS issue, possibly with gps.conf that came with the firmware?

I did not want to root the phone, but if fixing the gps.conf would solve the issue I'd do it.

LMY47X.G800FXXU1BPC4
G800FXXU1BOL1
TMH

APN has default,supl

gps.conf says (since it is not rooted, I can only read it):

NTP_SERVER=north-america.pool.ntp.org
XTRA_SERVER_1=http://gllto1.glpals.com/4day/v3/latest/lto2.dat
XTRA_SERVER_2=http://gllto2.glpals.com/4day/v3/latest/lto2.dat
SUPL_HOST=supl.google.com
SUPL_PORT=7275

Hello and welcome to Android Forums gligeti!

I doubt that rooting your device will help in this case. You are not the first to mention that the GPS lock on Lollipop is inferior to KitKat. If it is important to you then you could easily downgrade your firmware back to KitKat by downloading the stock T-Mobile firmware for Hungary and flashing it via Odin by following the instructions and video contained in the links of #1.11 of 42 Galaxy S5 models - Dummies Guide. Hopefully, this will help.

Stock Samsung KitKat firmware for T-Mobile, Hungary for the S5 mini...

Model SM-G800F
Model name GALAXY S5 mini
Country Hungary (T-mobile)
Version Android 4.4.2
Changelist 1998311
Build date Mon, 01 Dec 2014 06:49:07 +0000
Security Patch Level N/A
Product code TMH
PDA G800FXXU1ANL1
CSC G800FTMH1AOC1

 

[gligeti]

Hello and welcome to Android Forums gligeti!

I doubt that rooting your device will help in this case. You are not the first to mention that the GPS lock on Lollipop is inferior to KitKat. If it is important to you then you could easily downgrade your firmware back to KitKat by downloading the stock T-Mobile firmware for Hungary and flashing it via Odin by following the instructions and video contained in the links of #1.11 of 42 Galaxy S5 models - Dummies Guide. Hopefully, this will help.

Stock Samsung KitKat firmware for T-Mobile, Hungary for the S5 mini...

Model SM-G800F
Model name GALAXY S5 mini
Country Hungary (T-mobile)
Version Android 4.4.2
Changelist 1998311
Build date Mon, 01 Dec 2014 06:49:07 +0000
Security Patch Level N/A
Product code TMH
PDA G800FXXU1ANL1
CSC G800FTMH1AOC1

well, actually it worked on an interim 5.0.1 release that I cannot find anywhere anymore. It did not work well on KitKat either.
This 5.0.1 or so came out in the spring, and my GPS was working well with it until I upgraded to the current 5.1.1 late August. Could have been some special build with TMH?

 

[ironass]

There has never been an official Samsung Android 5.0.1, Lollipop, release for the T-Mobile, Hungary, Product Code, TMH. Straight from Android 4.4.2, KitKat, to 5.1.1, Lollipop. See, here.

 

[gligeti]

There has never been an official Samsung Android 5.0.1, Lollipop, release for the T-Mobile, Hungary, Product Code, TMH. Straight from Android 4.4.2, KitKat, to 5.1.1, Lollipop. See, here.

I saw that, that's what baffles me, that's what I meant when I said that I cannot find any traces of that version -- I am pretty sure it was 5.0.1, I got it through regular OTA in the spring of 2016 (I never installed anything with Odin on this phone, this was all "straight" factory and OTA, no root, no custom versions) -- and GPS was working with that very well until I got a new update that I installed late August -- that's the 5.1.1 I am on right now.

I certainly did not dream that . I am looking to see if there are any logs where I can potentially figure out the build number... I'd consider going back to that version only if I found it.


EDIT: Now looking at the other firmware versions, maybe it was a BPB2 and 5.1.1 -- I may remember 5.0.1 wrong. In many other countries this PB2 version is also listed, so they may have had it in Hungary too. Since PB means Feb of 2016 it could make sense as I got the OTA in the spring. (see Germany)

So, assuming this must be that version, let me rephrase: GPS was working robust with the G800FXXU1BPB2 version that they DID have for Hungary for a few months and it broke when I got the G800FXXU1BPC4 update.

 

[ironass]

Can't help you there I am afraid. I can find no Samsung official firmware being released for Android 5.0.1 on the G800F, at all.

 

[gligeti]

Can't help you there I am afraid. I can find no Samsung official firmware being released for Android 5.0.1 on the G800F, at all.

See my update. It must have been the earlier 5.1.1 G800FXXU1BPB2 build. Sorry for the confusion, "5.0.1" was just my recollection since I didn't realize that I apparently had an update from 5.1.1 to a newer 5.1.1. build.

Unfortunately it is not officially listed as ever been available for TMH.

EDIT: Sure enough there was a PB2 for TMH.

 

[gligeti]

Since there was some detour with my confusion with the versions, here is a consolidated version...

I had GPS work unreliably in one car under KitKat.
Update in the spring of '16 to (most likely) G800FXXU1BPB2 fixed it and made GPS work robust even in that environment (kept lock, always accurate enough for navi -- used it happily and reliably for months)
Update late summer of '16 to G800FXXU1BPC4 broke it again.

I also am noticing that even with A-GPS the satellites in view only show up once a fix is established (unlike on the other Galaxy models in the family that immediately show sats in view).

 

[ironass]

Since PB2 was never, ever, released for Product Code TMH, T-Mobile, Hungary, you must have downloaded it and flashed it to your phone as it would not have received it otherwise. Perhaps you could do the same again and see if that helps.

 

[gligeti]

Since PB2 was never, ever, released for Product Code TMH, T-Mobile, Hungary, you must have downloaded it and flashed it to your phone as it would not have received it otherwise. Perhaps you could do the same again and see if that helps.

I absolutely never flashed this phone. Both updates came OTA. 100% positive. BTW the first time (that I assume must have been the PB2) I got a notification that it is available, and installed straight from the notification I believe. The second time I actually clicked the check for update late August or so -- this is the current PC4.

I'll try downgrading to PB2 to see if it makes my GPS happy again -- although I am a little concerned to flash something from some unofficial source :-(.

 

[ironass]

The only way that it could have received an OTA update is if your phone has a Product Code other than that for T-Mobile, Hungary, TMH, as mentioned in your post #12. You can check your phone's Product Code as per #1.8 of 42 Galaxy S5 models - Dummies Guide

 

[gligeti]

The only way that it could have received an OTA update is if your phone has a Product Code other than that for T-Mobile, Hungary, TMH, as mentioned in your post #12. You can check your phone's Product Code as per #1.8 of 42 Galaxy S5 models - Dummies Guide

CSC: G800FTMH1BOL1

Phone info app says Product code SM2G800FZKATMH, and original, active and firmware CSC code are all reported TMH. "Available" CSC codes, whatever that may mean, is empty.

And yet, there is no doubt in my mind whatsoever that it was updated after I got a notification (even recall there was an icon in the notification bar). When I mean "OTA" I mean I did it all on the phone via WIFI, no PC, Odin or anything, straight from the notification (not from settings). It is a mystery then... Could it have been revoked? Could it have been some other TMH customized upgrade notification/method?

Anyway, I'll flash the TMH/PB2 (is Samsung-firmware.org's TMH-G800FXXU1BPB2-20160329110844.zip safe?) and we'll see if it restores my GPS functionality to what it used to be from the spring to Aug. If so, then I would be sure this is the firmware what my phone had in that timeframe.

 

[gligeti]

Update: Still haven't downgraded, but digged into it a little bit to try to figure out the previous firmware and found out about the recovery logs that you can dump from the recovery menu. Fortunately I haven't done many wipe caches so my relevant history is still available.

Re TMH PB2 version:
Looking at the recovery logs, the phone had G800FXXU1ANL1 originally, then (dumping log.7) on Apr 4 it got updated to G800FXXU1BPB2 -- the log shows it is updating from /data/fota/update.zip -- so it was clearly an OTA update, then updated to PBC4 on Aug 11 (as per log.5). So BPB2 must have been officially released. And the log references TMH many times, so it was for this CSC.

Re GPS:
So back to the original issue, whatever they changed, GPS was MUCH, MUCH better with BPB2 than with KitKat, and now it is bad again with PC4 (may be even worse than KitKat).

I have now both firmwares downloaded just in case, and odin 3.11.1, my hands are trembling. (While it is formally a downgrade, I think there is a chance that I don't have to wipe the data as it is really the same version...)


Update: More mystery. I reverted to G800FXXU1BPB2 (didn't need to factory reset), and GPS robustness did not return to how it was when I had that version. The only other change that may have to do with the issue is that in Aug when I received the PBC4 update, I had GPS constantly on as the Samsung weather widget was constantly polling GPS through the "unified daemon" or whatever, and had to disable its GPS stuff (and also installed a different weather app). I have uninstalled the other weather app to return to as close to the state when GPS was robust as possible, but still no success. Very strange. I want my GPS robustness back badly.

 

[gligeti]

Update: Still haven't downgraded, but digged into it a little bit to try to figure out the previous firmware and found out about the recovery logs that you can dump from the recovery menu. Fortunately I haven't done many wipe caches so my relevant history is still available.

Re TMH PB2 version:
Looking at the recovery logs, the phone had G800FXXU1ANL1 originally, then (dumping log.7) on Apr 4 it got updated to G800FXXU1BPB2 -- the log shows it is updating from /data/fota/update.zip -- so it was clearly an OTA update, then updated to PBC4 on Aug 11 (as per log.5). So BPB2 must have been officially released. And the log references TMH many times, so it was for this CSC.

Re GPS:
So back to the original issue, whatever they changed, GPS was MUCH, MUCH better with BPB2 than with KitKat, and now it is bad again with PC4 (may be even worse than KitKat).

I have now both firmwares downloaded just in case, and odin 3.11.1, my hands are trembling. (While it is formally a downgrade, I think there is a chance that I don't have to wipe the data as it is really the same version...)


Update: More mystery. I reverted to G800FXXU1BPB2 (didn't need to factory reset), and GPS robustness did not return to how it was when I had that version. The only other change that may have to do with the issue is that in Aug when I received the PBC4 update, I had GPS constantly on as the Samsung weather widget was constantly polling GPS through the "unified daemon" or whatever, and had to disable its GPS stuff (and also installed a different weather app). I have uninstalled the other weather app to return to as close to the state when GPS was robust as possible, but still no success. Very strange. I want my GPS robustness back badly.

More update. The downgrade didn't seem to make a difference, nor did the removal/reinstalling of different GPS-related apps (Here, Waze, GPS Toolbox and GPS test). I since re-upgraded to BPC4 with no change.

However, what I experience is that every now and then the GPS is working great, at other times it does not and it is clearly NOT related to weather/sky or sat constellation, nor with the compass calibration. I tried different variations of resetting it, reloading A-GPS, letting it get the data from the satellites (with airplane mode one), with no apparent correlation to how it is working. I even had a case where I was using Waze on a clear day, which constantly kept dropping the GPS lock, undercalculating my speed (which is typical when the GPS is acting up), and then after a phone call it re-locked and then kept the signal stable, displayed my correct speed (in narrow streets, I have a very reproducible area where it always puts me one street off when it is in the "bad mood" state). I returned for a test and driven through the same route again now with steady positioning and correct speed readings.

So it is some software issue, but somehow the reliable "stable" state for many months after the spring update was some kind of a side effect, possibly something to do with how the GPS got reset and first initialized after the upgrade.

Note again that it only affects the behavior with weak signals, in the other car with no windshield coating it always works correctly and stable. Also, it is not about the initial lock time or the inability to get a fix, it is about not keeping the lock and calculating inaccurate positions.

I'll keep playing to see if there is something I can find that causes it to break or work again.