[Samsung Epic 4G Touch] madocs:
Unfortunately, I've become a veteran when it comes to ET4G GPS problems.:(

This thread is intended to summarize ET4G GPS issues, reported fixes, troubleshooting advice, and GPS related conversation in hopes of determining the root cause. Could be fixable, could be hardware, but I really want to get to the bottom of it. Let’s try.

I have been all around XDA and the rest of the interwebs for solutions. My personal frustration has been that most GPS issue posts result in standard advice to: download GPS Test from the market, re-install your ROM, or get back to stock and start over. That's actually great advice, and I've pursued it - just doesn't make a difference for some of us. Still worth a shot though.

Several members have great threads concerning specific approaches, and I'll reference those members and threads here. I don’t know of a true fix, but some trickery/mods appear to help a bit.

I’ll do my best to keep this up to date – referenced threads will include their own updates. If/when a true GPS fix pops-up…that’d be super! Let me know so we can validate and kill this thread.

My reference of “True Fix” refers to getting a fast, consistent, nav worthy GPS lock as the default operation, meaning no special mods of config file edits or special software. Kinda like if the GPS functionality on the device actually did what it was supposed to do. Alot of these options assume that you have root, if you don't want to root your device, best to talk to your local sprint store instead of XDA. The bright side of this approach: it may be the best one if this is purely hardware.

SO, if you have crap GPS on your ET4G and you want to take ownership of the issue (including whatever hell breaks loose when you start changing stuff) here is a fairly comprehensive list of the hoops that you can jump through

at your own risk

:

#1 USER ERROR Maybe you messed it up. I’m no expert, so when I root a phone and load unsanctioned software on it…I look in the mirror when I have problems.

Go back to stock and play normal. Thank SFHUB for compiling a great thread with reference to root, revert and more.

Wipe and retry flashing a recent release of your favorite ROM. Thank BARNACLES10 who has compiled damn near everything here.

JUST_S has a thorough reference thread (including a GPS section) here.

QBKING77 provides another awesome resource. If you are like me, pictures help. Moving pictures help even more and Qbking makes scores of great preview and instructional picture shows for the community.
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#2 A-GPS tools Try augmenting your A-GPS by downloading apps that help your clear and refresh assisted GPS data and look for sats.

As I mentioned, Just_s has a GPS post on his reference thread listing apps and other goodies to try. I'm not trying replace that list, but will reference some of the same items as we'll refer to these in discussion of test results.

Here are the GPS helper apps that I've know of and have used:

GPS Test (has cool features even if your GPS is working great)

GPS Status & Toolbox

FasterFix

GPS Essentials

These apps are free and provide a myriad of GPS related stuff, including options to clear and update/refresh your A-GPS.
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#3 Dialer codes

Some dialer codes may require you to enter your MSL (see Just_s thread for how to get yours).

It may be possible to reset the GPS with a dialer code. A code that we used in the past ##GPSCLRX## worked on the EVO 4g. Some users report it to be working on the ET4G, but I have been unable to confirm. This code requests my MSL, but does not appear to reboot after entry (which is what occurred on the EVO when entered).

I would LOVE to provide a link to the ET4G dialer codes here, but until I find a great source and will hold off. Several of the threads I have seen reference other phones and appear to by copy/paste from prior lists. I can get some of them to work, but not all (including the GPSCLRX). I don't want to keep publishing those - I'll list confirmed as working ET4G dialer codes as I validate. Of course, there is a chance (see #1 above) that I am doing something wrong here and will update this section as soon as someone sets me straight. :)

update: Here are the dialer codes and tests that I've completed. Don't mess with these for fun, just use if you know what you are doing and you need them.

*#2580# - ServiceMode - Works!

*#RIL# - Sec_RIL_Dump - Has the LogFileList Works!

##RTN# - Real-Time Network (RTN) Works!

*#DATA*SCREEN*# - DataCreate Works!

*#0BAT# - BatteryStatus Works!

##UPST# - PhoneUtil - UART/USB Works!

##GPSCLRX# - Reset the GPS - Requires MSL [does

not

work on ET4G]

*#1472365# GpsSetup [does not work on ET4G]

*#INFO*1111# Testing [does not work on ET4G]

*#0*# LCD TEST [does not work on ET4G]

##DATA# - Data Programming - Requires MSL [NOT TESTED]

##DEBUG# - Debug Menu - Requires MSL [NOT TESTED]

##AKEY# - Data A key menu - Requires MSL [NOT TESTED]

##<MSL># - Master Subsidy Lock - Requires MSL [NOT TESTED]

*#0VIB# - Device Test - Vibration Test [NOT TESTED]

*#0MP3# - MelodyTest [NOT TESTED]

*#7780# - Factory data reset [NOT TESTED]

*#232331# - BluetoothTest [NOT TESTED]

*#2664# - Touchscreen Accuracy Test [NOT TESTED]

*#0RTC# - RTCTimeRead - Displays Date and [NOT TESTED]

*#9900# - SysDump [NOT TESTED]
​

Here are some options that are sprinkled throughout XDA, often in forums other than the ET4G.

#4 DRIVERS Leaving room for more here, but as of now there are reports that flashing an alternate GPS driver may do something. This could be a sasquatch siting, but perhaps the sasquatch knocks something into place when flashed from CWM.

EVO Driver. Tough for me to locate the origin of this one, but daryelv is credited elsewhere and ebuechler3 has this thread. This daryelv post includes the file for DL as well.

colorado_al provides a different file to flash in this thread. Thanks!

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#5 GPS Config file edits

At some point during your ET4G GPS woes, you ask yourself "what more can I do?", which is good! Sniffing around, you'll find that there is a config file used by the device GPS. There are some very interesting and quite brilliant mods being made here, with reports of improvement.

This thread by AngelDeath is incredible. AngelDeath bumped up the logic and intelligence of the GPS config. Impressive stuff, complete with fantastic write-up with pre-made files for your flashing consumption.

Xenova also has a great thread, providing instructions on making your own mods.

interloper also has a config file post here

#6 REPLACEMENT

Of course, taking the device back to Sprint and obtaining a replacement is an option. Might be a really good option and many members have reported it to resolve the issue.

If you took this approach, please share the experience. Specifically:

Did it resolve the issue or did you have to seek a 2nd replacement?

If resolved, did you notice anything identifyably different about the replacement like a different hardware version (menu>settings>about phone) or physical change?

How was the Sprint experience? Did they give you hell? Did they admit that they knew of an issue and were obliged to replace? Any information you can provide here could make it easier or faster for others.

If you have no GPS issues at all, congrats! For those of us that do, let's solidify what works and what doesn't. As great as it would be to find a fix, it will be equally rewarding to pin it down to certain devices so we can at least know that our only option is to exchange the device.

If you do jump in and post something along the lines of "my gps is working great :p ", please share your ROM, Baseband and Kernel in the hope that we'll discover a combo that is devoid of GPS bug.

I've personally clogged up other threads with meandering GPS talk, I hope this thread can help alleviate that issue while providing a place to discuss GPS specifically.