yashsingh1/xdaforums huggingface dataset:
[Samsung Epic 4G Touch] rocket321:
I think this discussion is for folks who have never had good gps the entire time they owned the phone across stock or other roms. If you have gps issues with only a particular rom only you should ask in that roms support thread.

Personally I have had great gps service across many roms on this phone which I bought used on cowboom. I agree there are times where after being left on for days it will no longer receive locks and must be reset, however if your phone has never locked or similar I'd have sprint or Samsung replace it. I can get locks inside my house no problem.
[Samsung Epic 4G Touch] wilnotdie:
I must have misunderstood too, because I thought this thread was for GPS problems with 3party ROMs. I'll need to read it thru again and unfollow if so.

I've had the GPS problem but have been trying allot of different ROMs without testing GPS each time. My bad.
[Samsung Epic 4G Touch] trancie27:
i believe i have found a fix to the GPS problem once and for all.

e4gtcm.blogspot(dot)com/2012/08/temporary-stock-ff18-from-emmc.html

sorry for the (dot) in the url, i cant post links yet

i followed these instructions to the letter, but you need to be running CWM6 for this to work, i installed a later nightly and it was packaged with CWM6.

boot into the temp rom, install the app GPS status & tool box, go outside, enable GPS, and run this app, hit menu, tools, manage A-GPS state

dont worry about the pop up and hit download, give it a moment and youll get a lock, make sure you have a data connection for this to work.

after i booted back into CM9, GPS locks with no problem!

i hope this helped!
[Samsung Epic 4G Touch] felimz:
How is this any different than Resetting and Redownloading A-GPS data from GPS Status on the main ROM?
[Samsung Epic 4G Touch] trancie27:
you know, i didnt actually try that....... if you have any luck doing so get back with me. cant believe i missed that >_<
[Samsung Epic 4G Touch] Cipherblox:
A-GPS is a bandaid, not a fix for the GPS. It can help lock faster, but it can't create a lock out of thin air.

I've been very busy (Work, Graduate School, moving, etc...) but I'm going to try and put some time into this this week.

My initial plan is to find a ROM where I am unable to get a GPS lock. Once I do, I'll hash mmcblk0 as well as all the partitions. I'll also grab an image of mmcblk0. After that I'll temp boot into a TW based ROM and do all of the same steps. Unless the NAND drivers are masking away hidden partitions (ie: Yellow Triangle) I should be able to find what changed.

My theory right now; however, is simply that the baseband has a small amount of L1/L2/L3 cache associated with it that (obviously) isn't affect by flashing. I'm going to try and pull some of the GPS files from a TW ROM - perhaps they are pulling from a more reliable server for the AGPS data.

-GP
[Samsung Epic 4G Touch] Hero_Guy:
Well sprint just fixed my GPS for me! Here's what you do and you're just going to need your MSL. I was on the stock rooted FH23 when I did this.

WARNING: EVERYTHING ON YOUR PHONE WILL BE WIPED INCLUDING PICTURES. BACK EVERYTHING UP AND TAKE OUT YOUR SD CARD.

Go into your dialer and dial ##786#

Select reset and type in your MSL

Your phone is Going to reboot and wipe everything including pics.

Let the activation thing finish and that should be it. I'm getting locks indoors instantly and if I do wait, it only takes a couple seconds. I've left my GPS on, toggled, and rebooted my phone and it sticks. I just did it today but so far it seems good!
[Samsung Epic 4G Touch] gosueric:
I don't understand why a hard reset (which is what a 786 is, with re-activation as well) would fix that, unless you had some app(s) that prevented the lock in the first place, which I doubt.

You could get the same results by doing ##4472579# (GPSCLRX) and typing in your MSL, which clears the GPS data, and doesn't wipe your phone.

Unless, of course, I'm wrong and a 786 does more than hard reset + re-activate your phone, but from working at a Store I'm pretty sure it doesn't.
[Samsung Epic 4G Touch] chris41g:
It resets more than the user partitions.. It resets efs data as well..
[Samsung Epic 4G Touch] jimmyh05:
So is this method recommended to fix GPS?
[Samsung Epic 4G Touch] chris41g:
That was just for info... I have not studied it, seems varied from user to user.
[Samsung Epic 4G Touch] JeremyMundell:
I'm very eagerly watching this thread. My GPS has given me nothing but trouble in Seattle. I had my phone replaced and it still loses lock everywhere. Might be the mountains and trees?

Anyway, I bought an external Bluetooth GPS unit and downloaded the Bluetooth GPS app from the Play store. If you pair the devices and "allow mock locations" in system settings, you get a perfect lock every time, all the time. It's not a true solution but this workaround has been treating me very well for $20.
[Samsung Epic 4G Touch] Cipherblox:
While we know a few things that are contained in the EFS, I don't think any of us have a conclusive list. I have cleared it before and it hasn't really affected my GPS. I would be surprised to find that it contains more than simply carrier information....
[Samsung Epic 4G Touch] rbaucom:
Please try the AOSP JellyBean 4.1.1 rom

As the rom where most can't get gps lock unless they locked on first with a gb rom before flashing.

http://xdaforums.com/showthread.php?t=1812078

[ALPHA5][ROM] AOSP JellyBean 4.1.1 [8/24/12]
[Samsung Epic 4G Touch] Bigt2003:
I do remember clearing efs was needed to fix GPS on my T-Mobile G2. Every couple of flashes I needed to wipe it again. Maybe that's what's going on when you flash a stock rom? Just a guess...
[Samsung Epic 4G Touch] AdhvanIt:
This isn't actually a E4GT specific issue.

Take a look at my sig. Every one of those devices that are not Google experience devices have this exact same issue with GPS and AOSP ROMs. I applaud you for trying to figure it out, but since the "fix" for each of them is the same (flash back to stock and get a GPS fix), I am fairly certain you're on a wild goose chase.

Also, it is not in any of the data that is stored within the system or kernel. If this were the case, flashing to stock to get the lock and restoring a nand would be pointless, as the nand does not allow existing data to remain.

It's possible that the issues are within the RFG partitions. Since Samsung devices don't allow use of fastboot, it's impossible to even pull them.

Edit: Good luck, regardless. I really do hope you are able to find the cause.
[Samsung Epic 4G Touch] Nannuq:
I did the same thing as Jeremymundell. Good enough solution for me.
[Samsung Epic 4G Touch] Cipherblox:
Google Experience doesn't mean anything. If you are supposed to be using the xtra.bin (AGPS file) and permissions are not working, then that is one thing that was wrong.

Flashing back to stock and getting a lock is bogus. I have never ever had to do that. Sometimes I have had to wait >10 minutes for a GPS lock, but all of the ROMs are able to get a lock - indicating a software problem. If you read the entire post instead of simply showing off an arrogant side, you would see that I acknowledge that whatever data assists the GPS in locking in a stock ROM must not be NAND but must be either A) Cached or B) on a hidden partition.

Unless we are not reading/writing to the EFS properly, clearing it isn't a solution. Many people have attempted to do this multiple times and it isn't any sort of magic fix.

Even if Samsung presented fastboot as an option, they would still have control over the NAND driver that allows the NAND to be mapped properly. We wouldn't magically get access to something unless it was an oversite on their part.

If anyone would like to attempt to completely reverse engineer Samsung's NAND driver (Which likely includes all of their wear leveling algorithms and bad block management) be my guest - but I don't see that being a very efficient way to attempting to find a problem.

-GP
[Samsung Epic 4G Touch] AdhvanIt:
1. Google experience does mean something. It means the device comes stock with AOSP. Not some crappy manufacturer skin. As I noted before, this happens on many devices that are not officially supported by AOSP when flashing an AOSP ROM.

2. When you run into the "GPS will not lock" issue on AOSP ROMs, it flat out does not lock. There is no amount of waiting that fixes this. What you've experienced is not the same.

3. Fastboot devices typically come out with an engineering version of the bootloader. If you brick those devices with the eng bootloader installed, it unlocks R/W access to all partitions. Evidenced in the HTC EVO3D (which also has this issue). Good thing it can be unbricked too.

4. Flashing back to stock based ROMs seems to work for everybody else. Why? Who knows. But it does. Again, I applaud you attempting to find a real fix for it, as the current one is time consuming and obnoxious. Fortunately, we have to go back to stock based ROMs to do PRL and profile upgrades anyway and can just take care of that at the same time.

5. It's never been necessary to flash back to a GB ROM. Just a touchwiz ROM. All touchwiz ROMs are essentially stock...

6. If a missing binary or bad permissions were the only issues, I'm thinking they would have been found already.

Doesn't this thread belong in general? http://xdaforums.com/showthread.php?t=1268451
[Samsung Epic 4G Touch] Cipherblox:
1. So they come with a stock Android experience. What on earth does that matter other than other people are coding the ROM outside of those of us at XDA? Not sure why you seem to think that official support means anything when we can write everything ourselves.

2. So you have waited for 10 mins? 20 mins? 30 mins? Longer? I've had the E4GT since it came out and have never once had it not make a lock period.

3. We don't have a problem writing to wherever we want on our phones. Unless the driver is masking a particular partition or block of the NAND (Possible), we already have the ability to R/W anywhere.

4/5. Why is this relevant? I don't care that some ridiculous fix appears to work, I'm attempting to fix it.

6. Because no one ever makes a coding mistake.... Not only that, where did I suggest that this was a permission issue (What is a "binary" issue?). I found evidence that it could be a contributing factor - Chris41g even confirmed that, despite the fact that Stock ROM's don't use AGPS, his do.

Why would it belong in General? I'm actively reverse engineering the GPS Daemon and as soon as I get 3 seconds to put together, I can flash MD5, dd mmcblk0, and diff that against other ROMs. Sounds like a whole lot of development to me -- sorry I'm not meeting your levels of development.

Look, either contribute something to the development here or just stop posting here and taking up my time with this meaningless argument...

-GP
[Samsung Epic 4G Touch] Easy10pins:
Well thanks to the info in this and other threads, I now get a lock on at least 9 sats in under 10 seconds. I'm currently using AOSP Jellybean.
[Samsung Epic 4G Touch] Bigt2003:
Minus the trolling, this is a good thread. Team CM is already working on adding PRL updates to Aosp roms, and GP is working on GPS. If you don't want to help make improvements, go buy an iPhone.
[Samsung Epic 4G Touch] eddie3130:
I just got an instant lock on my location with Gmaps. I recently went from Mijjz latest Goodness(Which never was able to get a gps lock) to Agats fh23 stock rom(Working great so far). Also flipped on Mock location on
[Samsung Epic 4G Touch] mikeprachar:
I am running the Rogue CM9 Beta 1, and I get NO lock at all; period. Even though I appreciate it isn't a "real" fix, I am planning to flash a TouchWiz ROM, get GPS lock, and then go back. However, I haven't seen an answer to this:

1. Can I backup my current ROM in CWM recovery (packaged with ROM) and then restore that or do I have to flash a fresh ROM over the TouchWiz?

Thanks!
[Samsung Epic 4G Touch] Bigt2003:
Yes, that's all it takes. Did you try anything else first like GPS aid or GPS status to get a lock? What is your ntp server set to?
[Samsung Epic 4G Touch] mikeprachar:
I set the ntp to the North American one with Faster Fix. GPS Status shows "ON" but zero satellites in view. If I run a mapping program I get "Searching for GPS" in the status bar forever. I am installing GPS Aids now but I think it's the same utilities packaged differently...

If it helps; I don't believe I EVER tried to get a GPS lock on this phone after activating it - I immediately rooted it and set it up...

UPDATE: GPS Aids also gives me zero satellites

UPDATE #2: Temp Boot to EL29 worked perfectly; I can see why it's hard to keep people's attention on finding the real problem once you find a workaround...
[Samsung Epic 4G Touch] quasarsky:
i'm using the recalked rom. i had to flash to GB for gps lock before using the 1.6 calk before he quit supporting it. i didn't think using the recalked would bork my gps but it did. it locks slowly, even after initial lock and left on. and i have to use gps status to even get the locking started. i really don't feel like flashing back to GB just to get a lock for this. if anyone can fix the gps let me know! :).

i might just do a nandroid backup, flash to gb, lock, then restore my install. that should work no?
[Samsung Epic 4G Touch] nmarnier:
I took the long way due to not following directions closely enough, but yes it does work... thanks to qbking77 for all of his epic 4g touch bids to get my brick back on board and working better than ever.
[Samsung Epic 4G Touch] turbomeister:
Not a dev, but going to relay my experience.

I've experienced many of the same problems people have had with GPS. I've tried just about every "solution" to no avail. I finally decided to exchange the device. The new device displayed the same symptoms, causing me to believe it was a software issue that just needed time for a fix to be made.

Fast forward 1 year. I try out ff18 ota as well as fh13 ota, with no success. I tried the blu kuban rom as well as all the other solutions i could find on this and other forums. No success. I decided to exchange the device for another model. I go into a sprint store and play with both black and white E4GTs on display. The black one was exactly the same as both my previous devices. But the white? Flawless. I decided to take a chance and ordered a white one to replace my black one.

Its been almost 2 weeks, and I've been getting locks consistently even after 2 or 3 days without rebooting and constantly testing how many locks i can get every few hours. I'm now a happy GPS camper.

Everywhere i searched, people say there is no difference between the black and white model. Perhaps not. Could it be a bad batch? Luck of the manufacturing draw, like a lottery? My anecdotal evidence suggests that this is the case. I continue to test the GPS successfully when both of my previous e4gts would have failed miserably by now.

My new white phone is stock fh13 unrooted with no gps toolboxes or other similar apps installed. No changes to anything. Im afraid to root this thing or install any roms for fear of losing my long desired ability to use GPS consistently, like it was designed to.

When troubleshooting stuff like this, it is my experience that if software is the same and the results of tests between multiple devices are different, your problem is hardware. The random flashing errors from the factory are a caveat, but still something to consider.

FWIW.

[EDIT] It's been several days since my post. I continue to have success with my locks, even when I'm indoors. It would take <15s on average. I'm developing trust in my device through constant, and successful activations of the GPS. I want to note that I do not notice any jitteriness of the signal; it is smooth and steady. I do have every setting enabled in location services and am in the San Bernardino and Orange County portions of California. I hardly ever reboot the device.
[Samsung Epic 4G Touch] mikeprachar:
I did the flash-back to tempboot EL29 last week and it worked perfectly. I went from fully setup CM9 beta to temp EL29 and then reflashed the CM9 ROM. all my settings/data were still there; piece of cake.
[Samsung Epic 4G Touch] Bigt2003:
Here is my efs folder, I'm getting locks in about 3 seconds after wiping this, then going back to stock. If anyone is getting no lock, try pushing this to your root directory. I just want to completely rule out the efs before I start doing thru these roms line by line.

Not a flashable zip, sorry. http://db.tt/PEoSv2zX
[Samsung Epic 4G Touch] kash26:
Faster Fix worked for me, thank you.
[Samsung Epic 4G Touch] Snazarian:
Sad to say fasterfix didnt do anything for me,,,if anything i think using it to set my region made things worse actually :confused:
[Samsung Epic 4G Touch] Cipherblox:
Sorry I haven't been so active here everyone. Wife and I are closing on our first house today! Afterwards I'll pick up the work again.
[Samsung Epic 4G Touch] Easy10pins:
Easy way to fix the GPS is I picked up a GlobalSat Bluetooth GPS receiver that I keep hidden in my glove box. It's rechargeable and provides about 10 hours of on-time with an auto off feature. Now I always have GPS through BT with at least 13-15 satellites visible and almost immediate lock.

It's not a direct fix but it works great.

GPS has been hit or miss on every Android device I have ever owned. This little doohicky solved it all.
[Samsung Epic 4G Touch] Caferacer:
I've always had good luck with using fasterfix in conjunction with 'GPS tools'. It allows you to clear and reset the GPS state. Clear the state, reset, then reset the NTP server with faster fix. On my e4gt it's been getting very quick locks (Under 10s) consistently. GPS tools also allows you to see how many satellites and their general direction are being locked on.
[Samsung Epic 4G Touch] EL TEJANO:
I'm on the Paranoid Android rom, I'm trying to use the QPST application posted in this thread. One of the steps is to open the dialer & type in ##8778#, but when I do that nothing happens. When I was on the Blu Kuban rom & did that it would take me to the needed menu. Any way to get around that on this rom & make that menu appear?
[Samsung Epic 4G Touch] SOHKis:
try flashing a tw based rom
[Samsung Epic 4G Touch] Bigt2003:
^^^ What he said.

You can't access that menu from anything but a touchwiz rom. But if you just used QPST, it shouldn't have been affected by flashing Paranoid.

P.S. I'm using PA 2.15, and Faster Fix worked for me.
[Samsung Epic 4G Touch] te45a:
None of the AOSP have ability to do this yet, PA is based on CM10, BlueCuban is TouchWiz based so it can do this, same thing with PRL and 3G profile updates, works on TW ROMs, not working on AOSP... yet
[Samsung Epic 4G Touch] garfnodie:
Are we sure it's software and not hardware?

I've been running various ROM's for a while and didn't have a lick of problems with my GPS. Then after using an AOKP JB ROM for a week, my GPS started acting flaky. Tried CM10 then and still having problems, I'm back on CM9 that was working fine before and its getting progressively worse. It's very sporadic though as well. It can work flawlessly for a day, then hardly work at all the next.

Then there's my father's phone. He's got an E4GT as well, totally stock, no root, and he's on his fourth phone. Exchanged through Sprint store every time for GPS issues.

Sent from my SGSII E4GT using the XDA Premium app.
[Samsung Epic 4G Touch] robert93436:
sorry for the old post here, i used this app here https://play.google.com/store/apps/details?id=com.eclipsim.gpsstatus2&hl=en, i was able to get a lock inside my house after lining up my phone with the gps sat
[Samsung Epic 4G Touch] garfnodie:
Almost everyone here already uses this app to test their GPS, it's how me know were not getting any locks or only one sat and not three or more needed for a proper lock.
[Samsung Epic 4G Touch] Cipherblox:
Hi all. So sorry for delayed response. My wife and I just moved and I hadn't been able to put a lot of time towards this until recently.

I tried flashing multiple TouchWiz ROM's (GB and ICS), I tried different radios, and I tried flashing back to CM9. I tried wiping the EFS and flashing multiple radios, but I wasn't able to lock consistently or quickly either.

While it is possible that we just have a terrible GPS receiver, it just seems highly unlikely to me that hardware just doesn't work. If we were all able to lock in specific conditions or something, I would say our GPS receiver is just bad; but, it just seems like it HAS to be something on the software side.

Perhaps the firmware is where I should be looking....

Hurricane Sandy is really coming in strong, but I'll try and get some more progress.

-GP
[Samsung Epic 4G Touch] garfnodie:
I'll preface this by stating that I'm not a programmer. My experience with code never went beyond basic HTML many years ago.

Anyway, it seems to me like everyone has tried almost all there is to do on the software side. Stock unrooted, stock rooted, rooted with custom ROM's all have very sporadic results. As I stated before, I didn't have a lick of problems from the day I got the phone for months, and I'm a bit of a flashaholic, and then, out of the blue, it started to get flakey and is getting progressively worse. Even my father and step mother have both had mild to severe issues, they are both totally stock and unrooted.

Now I hope I'm wrong and just pulling 5h17 out of my ass here, as I'm pretty much stuck with this phone for another year+, and I use my GPS a lot for delivering pizza.

Anyway, I anxiously await your foray into the firmware to see if you can fix it.
[Samsung Epic 4G Touch] Gazzuk:
So about a year ago I got my wife and myseld the e4gt. She went with white and me black. Since day one I was having shaky gps locks. From time to time id get an accurate lock but 9 times out of 10 it wasnt locking. However for my wife her white e4gt has had locks like no tomorrow. Ive updated her from gb to ics and jb she always has a lock. Did sprint release gps fixes with the white model? Anyone with a white model e4gt with gps issues?

Dont let this thread die lol
[Samsung Epic 4G Touch] MykalDre:
I have the white model and the only time I ever had gps problems was on cm10. Flashed Exit_Only's gps fix and I got a instant lock. Whenever my gps gets off on new roms I just flash his tweaks.
[Samsung Epic 4G Touch] Gazzuk:
Yea I have his tweak. I just did a ##786# reset and applied his tweak with still no success. I dont ever show any satellites bars in any gps app from market I imagine if they did show id have an accurate lock. Anyone have suggestions on getting the gps satellites to show atleast a connection?
[Samsung Epic 4G Touch] MykalDre:
Whats your rom?
[Samsung Epic 4G Touch] Gazzuk:
Its the same story for me in gb ics and jb this time im on the fk23 leaked rooted rom and modem.
[Samsung Epic 4G Touch] pcmanager:
When I took my phone into sprint for the GPS problem the tech brought the phone out and said they had updated the GPS software? add then I opened GPS status after rebooting the phone and showed her that it was not connecting to any satellites on a stock ROM. She also had the galaxy s2 as for personal phone, I had her download the GPS status application from the play store . When she saw that her phone was locking and pulling in about 10 Satelites and my phone still have 0 she swap the phone out, incidentally to a new white GS 2. The phone now locks pretty good most of the time. If you're getting no locks anywere I would definitely try and get them to replace the phone.
[Samsung Epic 4G Touch] Gazzuk:
Well my brother is the manager for a sprint repair store ill see what he says.
[Samsung Epic 4G Touch] drilus:
I flashed the GPS fix on this page: http://xdaforums.com/showthread.php?t=1975379 . Cleared the Google Maps data and launched it again. I had a lock in 10 seconds. The GPS Status apps show I'm seeing 8 sats. Before I couldn't see any sats.