iOS4 update - now iPhone now reboots during phone call

Also having the same issue on a 3GS 16gb annoying as anything anywhere between 5 - 20mins causes a reboot phone doesn't appear to be getting hot or anything.

Have tried using a headset while leaving the phone laying down so the sensors don't seem to have any affect the issue is still happening for me.

This is an absolute nightmare and should be fixed ASAP!

I have downgraded from iOS4 to 3.1.2. I've had one very long call (28 minutes) since then and no reboot. So, it seems that the problem is not with the new baseband, but with something else in the new firmware. There doesn't seem to be any user ascertainable common characteristic - some people have non-jailbroken, installed as new phones with no additional apps and they're still getting it. I've never had a problem like this before - how do you escalate it with Apple?

Just to add my name to the list of this problem. iPhone 3GS, a few months old, no hacks, standard everthing. Worked fine before upgrade to iOS4, and has been fine after upgrade until I made my first long call today and it restarted three times during it.

My (UK) O2 reception's been pretty poor too, but then it's hard to see a difference there, because that's pretty standard. 😉

I have another thought that I'm going to try. I'll re-upgrade to iOS4 and then switch off my email pull and push notifications. For me, the problem seems to happen at different points in the call which seems strange if it's software driven. No doubt there are many things going on in the background, but one thing that's definitely happening is the periodic connecting for email and also a connection for notifications. It may be a waste of time, but I'll give it a shot.

In my case, I get rebooting every 5-10 minutes in any application, not just calls. I too thought this must be a battery issue but now it doesn't seem so. Unless we have two issues, that is: one where you get general rebooting and one that only happens during calls. So, can I clarify that people with OEM genuine apple batteries are still getting the issue where the phone reboots randomly when doing ANYTHING on the phone, not just making calls?

Here's a tip that seems to work for me.
I'm on a iPhone 3GS 16Gb and had the same problems all the rest of you a describing. Had this idea that it might be the new multitasking hook causing the problem, especially with "non-iOS4-tested-apps".

So I did this:
1. Double-tab home button, running apps showing
2. Press down on a random app, like when deleting apps
3. Press "-" on all NON-APPLE apps = closing them
4. Don't lanuch any 3rd party apps and make test call

My call lastet 30 mins, no reboots.

It's not the "right" solution, but seems to be a work around.
Unistalling all "non-iOS4-tested-apps" should be next obvious step.

I have exact same problem here with 16GB 3GS.

No jailbreak, worked perfect before, but I do have waterdamage (without any further problems though).
After the update to iOS4 I got the infamous 'error 29'. Fixed this problem using Blackra!n to break the never-ending-Reboot-chain (for a reason iRecovery didn't work).

How did you manage to downgrade it to 3.1.2?
Can u post ur trick, please?

Any other solutions are very welcome!!!!

New problem: Battery doesn't charge anymore... 0% and unable to connect to USB/iTunes.

So people, don't wait till you've reached the 0%, because I think you're pretty f...ed at that certain moment.

Today I could do an outbound call for 22 minutes withoput any reboot using my bluetooth car kit. Was talking with a friend with the same 3GS iPhone and he has no problems at all, everythings working perfectly fine with iOS4. So there seem to be some hardware differences between iPhones, that affect this problem.

I stopped all apps in background and made a call with the exact same reboot occuring at 6.04mins

I then made a call 10mins after that which didn't reboot and lasted around 15minutes - the longest since i upgraded!

I have now factory restored the phone and am currently restoring my contacts, i will post back if it makes a difference - Come on Apple are you dealing with this?? It is costing my business money!

Hello i am in france and i have same problems iphone rebbot on call. I made full restore twice. create new profile same problem. But before to make a call i stopped all soft in background and no problem 45minutes call ..... Iphone 3gs 32gb

"New problem: Battery doesn't charge anymore... 0% and unable to connect to USB/iTunes.

So people, don't wait till you've reached the 0%, because I think you're pretty f...ed at that certain moment."


Now THAT is scary. Anyone else experiencing this? I'm afraid to test it myself..

Update: Got back onto Applecare today to report back that a fresh download of iOS4 didn't work and it still reboots during a call - and only during a call, it's been fine all day with other normal usage. I have not installed any apps other that what the OS shipped with, my calendar and contacts, there were no other apps running, just the phone app, it has never been jailbroken or had a battery replaced. All as shipped from Apple except the OS. It still reboots during calls.

The solution as I can't downgrade to v3.1.3 is a new handset on Sat @ the local Applestore. Appointment booked and they have stock of iOS3.1.3 3GS 16Gb as a replacement for me!

If only I could downgrade....

Same problem for me, just adding to the thread to bump it to the front page again as no doubt more people will have the same problem.

The odd reboot outside of calls but every 10 minutes during a call.

Same problem to me, 3GS 32 GB, not Jailbreak or anything else. German T-Mobile Operator. I did a restore twice and first it seemed to work for a half day and then the problem came back. Yesterday the problem was there at each call I did. Today at noon the first reebot during a phone call. Later I connected via Bluetooth in my car (HFP) and no problem.
It is hard to fin a pattern, but this is really disappointing. I was not used to get such a quality from Apple.
Apple, you should fix this problem very fast because the main element for an Phone is not working really reliable.
Overall there seem to be a lot of further problems with iOS 4:
* Forwarding an Email didn't allow me to write any Text in the eMail
* Putting Apps in a folder resulted in an error and all folders have been lost and I had to start new
* Organizing Apps through iTunes needed several attempts to get it done, the sorting order was lost for several times

Seems to mee that Apple released a green apple which is not ready to harvest.

Reinhard