Results 1 to 6 of 6
Discuss Does 3GS GPS chip stop working when WiFi is switched off? at the iPhone 3GS - Hackint0sh.org; I can't figure out why my 32GB 3GS is behaving this way. I use the ...
  1. #1
    Supporter Array

    Join Date
    Feb 2012
    Posts
    16
    Post Thanks / Like
    Downloads
    0
    Uploads
    0
    Rep Power
    0

    Default Does 3GS GPS chip stop working when WiFi is switched off?

    I can't figure out why my 32GB 3GS is behaving this way.

    I use the "Maps" app that came with it, and it seems to work pretty well when Ihave both WiFi and Cellular Network Data turned on. I also use Trimble Outdoors Navigation, it also seems to work fiarly well. At least it can find where I am, within a few hundred yards. Not the accuracy I usually get with my old Garmin Emap, but at least it's something.

    But when I turn off WiFi (using "Settings/General"), suddenly the 3GS hasn't a clue where it is, whether you're running the "Maps" app or the Trimble app. With WiFi on, it usually takes a few minutes to figure out where it is, but then it comes thru fine. Not so when WiFi is off - I can stand in one spot for 10 minutes or more in a clear outdoor area, with either app, and it keeps showing where I was early in the morning, 12 miles away. Obviously it isn't getting a GPS fix.

    Anybody know why it seems to lose its way when ***WiFi*** is turned off? I would have thought the GPS chip doesn't need WiFi's help.

    a 3GS *does* have a GPS chip, doesn't it?



  2. #2
    Super Moderator Array n1ckn4m3's Avatar

    Join Date
    Mar 2009
    Location
    USA
    Posts
    2,717
    Post Thanks / Like
    Downloads
    0
    Uploads
    0
    Rep Power
    145

    Default

    If I recall correctly (possible I don't, but I'll try anyways) the GPS in the iPhone 3G/3GS was AGPS, which is assisted by either cellular triangulation and/or WiFi network IP location lookups. The GPS lookup without either of the assists can take as long as 15 minutes to complete. Commonly, this is misrepresented -- people believe that since the iPhone 3G/S are AGPS devices that they cannot work without cellular network or data connectivity, but this is false. The device does have a standard GPS receiver, but it takes an inordinately long time for it to determine the proper satellite information and adjust, as this is what it uses the location data from your cell tower or data connection to do.

    So, the GPS doesn't *need* the WiFi or Cellular help to function, it's just that it functions EXTREMELY slowly without it. Doing a simple test, it took my old 3GS phone more than 20 minutes to properly determine my location with both wifi and 3g/edge disabled. Beyond that, since I didn't have cellular data or WiFi, it couldn't load the map anyway, and all I ended up seeing was a blue dot in the middle of a grey sea.

    Additionally, if you have installed the 06.15.00 baseband (iPad baseband) to unlock your device, this can permanently disable your GPS function and it will only function as AGPS, requiring wifi or cell data to triangulate your position.
    The preceding forum post has been brought to you by the letter "N" and the number 42.

    iPhone 4, 32GB (iOS 6.1.2 | evasi0n | SHSH: 4.0 - 6.1.2)
    iPad 2 3G, 64GB (iOS 6.1.2 | evasi0n
    |
    SHSH: 4.3 & 4.3.3 - 6.1)

    Restore problems? Read this: http://www.hackint0sh.org/f137/130802.htm

    Did we solve your problem? Got a dollar or two spare? Please Donate!


  3. Thanks Little-Acorn thanked for this post.
  4. #3
    Supporter Array

    Join Date
    Feb 2012
    Posts
    16
    Post Thanks / Like
    Downloads
    0
    Uploads
    0
    Rep Power
    0

    Default

    Quote Originally Posted by n1ckn4m3 View Post
    Additionally, if you have installed the 06.15.00 baseband (iPad baseband) to unlock your device, this can permanently disable your GPS function and it will only function as AGPS, requiring wifi or cell data to triangulate your position.
    I bought this 3GS used, and found (with your help) that the previous owner had jailbroken and unlocked it. I just slipped my T-Mobile SIM chip in it, and voila, it cam eup and worked perfect. Or apparently so. I could make and receive calls, use cellular data, tune into my house's WiFi, the MAPs application could find where I was and track me, all the goodies seemed to work.

    Then I noticed the Maps wasn't quate as accurate as my old Garmin Emap GPS, whihc has often told me where a geocache was within 10 feet (and it's not WAAS-enhanced!). This 3GS would get me within several blocks, at best. Still, it mostly worked.

    Then I found that if I switched off WiFi, it couldn't locate me, like ever.

    Others told me that if the phone's Modem software had been changed to 06.15.00, the GPS would be disabled. And now you are confirming that. And sure enough, my 3GS's Modem Software *is* 06.15.00.

    Hmmm.

    Do you know if ther is any way to get the old Modem software BACK onto this 3GS, while still leaving it jailbroken and unlocked? Even if I have to do some sort of Master Reset and lose all my apps, that's cool because I have nothing but free ones so far and I can get them back later. I'd REALLY like to get that GPS chip going again, if there's any way to do it.

    If that can't be done, then I have another question: If I were to sell this 3GS and buy another that is NOT jailbroken or unlocked, and whose GPS chip is working fine, is there a way I can "carefully" jailbreak the new one and unlock it so that I can use it on T-Mobile, but the original Modem Software stays in place and I can still keep the GPS chip running?

    One fellow told me that if I found an older 3GS that had never had its software upgraded via iTunes, and still had an older Modem software in place, than it was possible to jailbreak it using "the right software" such that that older modem Software would stay, but the IOS could be upgraded to 5.0.1, and the phone could then connect to T-Mobile while retaining the use of the GPS chip. Any truth to this rumor? What program is "the right software" for this kind of jailbreaking?
    Last edited by Little-Acorn; 03-06-2012 at 01:07 AM.

  5. #4
    Super Moderator Array n1ckn4m3's Avatar

    Join Date
    Mar 2009
    Location
    USA
    Posts
    2,717
    Post Thanks / Like
    Downloads
    0
    Uploads
    0
    Rep Power
    145

    Default

    Unfortunately, there is not a way to downgrade this baseband. The documentation provided with it (though I know you didn't upgrade it) clearly states that this is a one way journey -- there's no way to undo it, there's no way to go back. The *only* way would be to physically desolder the baseband chip and replace it with a baseband that had the lower revision. You can find these baseband chips online, but it's a very in-depth repair to do so.

    As far as your ability to purchase a new one, it really depends on the baseband that the phone has. Do a quick google search and you'll end up at the iPhone Wiki page that shows current unlockable basebands and the current shipping basebands. It's not guaranteed you'll get a phone that can be unlocked, so you will need to do your homework to make sure.

    Unfortunately, your friend was incorrect or misunderstood what he had read. There is no way to downgrade the modem firmware on a 3GS.
    The preceding forum post has been brought to you by the letter "N" and the number 42.

    iPhone 4, 32GB (iOS 6.1.2 | evasi0n | SHSH: 4.0 - 6.1.2)
    iPad 2 3G, 64GB (iOS 6.1.2 | evasi0n
    |
    SHSH: 4.3 & 4.3.3 - 6.1)

    Restore problems? Read this: http://www.hackint0sh.org/f137/130802.htm

    Did we solve your problem? Got a dollar or two spare? Please Donate!


  6. Thanks Little-Acorn thanked for this post.
  7. #5
    Supporter Array

    Join Date
    Feb 2012
    Posts
    16
    Post Thanks / Like
    Downloads
    0
    Uploads
    0
    Rep Power
    0

    Default

    Thank you NickName, I found a list of unlockable basebands at
    Unlockable Basebands !

    Is that the one you were referring to?

    My 3GS now has 06.15.00, I don't know what it originally came with. The page I indicated says that this version cannot be reversed, and has been known to cause the GPS chip to stop working. I'm pretty sure that's my situation.

    I'll start a new thread to further investigate this, since the title of this one is pretty far removed from the subject. Thanks for your help!


  8. #6
    Super Moderator Array n1ckn4m3's Avatar

    Join Date
    Mar 2009
    Location
    USA
    Posts
    2,717
    Post Thanks / Like
    Downloads
    0
    Uploads
    0
    Rep Power
    145

    Default

    No problem. They've been trying to work out a fix for the GPS issues or at least be able to downgrade the baseband, but unfortunately there really hasn't been much activity on that front for the last 6-8 months... Good luck!
    The preceding forum post has been brought to you by the letter "N" and the number 42.

    iPhone 4, 32GB (iOS 6.1.2 | evasi0n | SHSH: 4.0 - 6.1.2)
    iPad 2 3G, 64GB (iOS 6.1.2 | evasi0n
    |
    SHSH: 4.3 & 4.3.3 - 6.1)

    Restore problems? Read this: http://www.hackint0sh.org/f137/130802.htm

    Did we solve your problem? Got a dollar or two spare? Please Donate!


 

 

Similar Threads

  1. USB's stop working?
    By LilSnoo4p0 in forum Installation
    Replies: 3
    Last Post: 04-16-2010, 07:55 PM
  2. [Problem] usb stop working
    By kazrual in forum Hardware
    Replies: 1
    Last Post: 08-13-2009, 04:51 PM
  3. Installer Stop Working on 3G iPhone ver 2.2.1
    By razori in forum Free Toolchain Software (Cydia App's)
    Replies: 0
    Last Post: 04-02-2009, 07:42 PM
  4. [Alarm] Not working when phone switched off
    By X3n0 Ac|d in forum General
    Replies: 4
    Last Post: 05-11-2008, 11:10 PM
  5. {wifi woes} unknown unlock has caused it to stop working
    By tony pops in forum iPhone "2G" (Rev. 1)
    Replies: 2
    Last Post: 04-17-2008, 06:06 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBulletin®
Copyright © 2014 vBulletin Solutions, Inc. All rights reserved.
Search Engine Friendly URLs by vBSEO
(c) 2006-2012 Hackint0sh.org
All times are GMT +2. The time now is 07:54 PM.
twitter, follow us!