Help, GPS stopped working on 3G after downgrade to 3.1.3

[yaronkle]

Hi,

I have an unlocked iPhone 3G that had IOS 4.2.1. It would run very slow and at times drain the battery in 1 hour.
Tried clean wipe, SAM... eventually gave up.

Downgraded to IOS 3.1.3 and the phone is now fast, and the battery lasts a day and a half.
Unfortunately the GPS stopped working.
I see that my baseband is 05.15.04.

Does the GPS in baseband 05.15.04 work with IOS 3.1.3?
Can I downgrade the baseband?
If I must upgrade back to IOS 4.X, which is the best version for the iPhone 3G?

Thanks!

[Mes]

I have an unlocked iPhone 3G ...

Do you mean 'factory unlocked, unlocked by Apple'?

... It would run very slow and at times drain the battery in 1 hour. Tried clean wipe, SAM... eventually gave up.

SAM works for most people. Was PUSH working? "Push Checker" also checks if your push certificate is unique.

...Does the GPS in baseband 05.15.04 work with IOS 3.1.3?
Can I downgrade the baseband? ...

It should. The baseband can not be downgraded.

If I must upgrade back to IOS 4.X, which is the best version for the iPhone 3G?...

4.2.1.

[yaronkle]

Hi Mes,

The phone was unlocked by Apple. I did not enable PUSH, so I don't know.
Upgrading to IOS 4.X is the last resort. but it's so slow on the 3G and I already tried it twice but it did not fix the battery issues.

Any suggestions as to how to enable GPS on 3.1.3 (location services is enabled)?
Thanks.

[Mes]

With a factory unlocked iPhone, any SIM and PUSH are authorized and SAM is not needed.
Trying installing a PUSH app, like iPusher from the App Store. Keep the phone connected
It may take awhile to get it working. One it works, you can disable notifications.

Now check the battery usage. If it's better it's time to work on the GPS problem.
I would try restoring 3.1.3 from stock, jailbreak w/redsn0w 0.9.4. Activate, verify PUSH,
then check GPS again.

I would not install 4.2.1 unless everything else failed

Good luck.

[yaronkle]

The phone was locked when it was bought. Apple unlocked it a year after the purchase.
I don't care for PUSH and my battery is great with 3.1.3.
My only problem with 3.1.3 is the GPS.

Will try 3.1.3 again.

Thanks.

[Mes]

You're welcome.

Another restore sometimes fixes strange behavior.

The reason I suggested getting push working, was to verify authorized certificates. Once that is done, turning off Notifications in Settings disables push completely.

[yaronkle]

I reinstalled 3.1.3 without jailbreaking. google maps could not pinpoint me correctly. Looks like a 100 meter radius.

Installed 4.2.1 and accuracy is much better but still not good. Accuracy is 328FT.
I am starting to think that the problem is with the GPS itself and not the version.

Going back to 3.1.3 since 4.2.1 is terribly slow.

[Mes]

Good GPS accuracy needs signals from several satellites, good map data, .. and .. a good iPhone :
Something is different between the two versions. iPhones are GPS assisted using cellular & WiFi location data. Sounds like the gps is not working at all. Typical with the iPad 6.15 BB installed.

3.1.3 is the best. Cheers

[yaronkle]

Thanks,

I'm back to 3.1.3, jailbroken and restored my backup (one which I did right before I started playing with the phone).
The battery started pulling 1% every 30 seconds and eventually stabilized on 91%.
iPusher showed that push notifications works. Disabled push since then.
GPS looks ... dead.

Update: It looks like a HW problem.
If I press the screen MAPS pinpoints my location with a radius of approx. 20 meters.
I opened the iPhone and located connector 6 (should be the GPS connector from what I read) but it was in place.

GPS still dead though.

[Mes]

Take a look at the repair manuals on iFixit: The free repair manual