IOS 4.2.1 battery drain

Eric Shawn2 wrote:

Jonathan Christensen wrote:

Lawrence Finch wrote:

I rolled back to IOS 4.1. My phone isn't a jailbreak. It wasn't that difficult.

I'm very curious in how you managed to do that. Once you upgrade to a newer iOS, the only way to downgrade is to jailbreak your phone. At least that's the only method I've ever heard of. Thanks.

Well, first let me say that I hated iTunes 10. So much so that I reverted back to 9.2.1 within days. So, when IOS 4.2 came out, and it required iTunes 10...I installed it on my Macbook instead of my MacPro system. The MacPro is the system I always connect my iPhone to. It has all my backups.

So after installing, iTunes 10 on my MacBook, and updating to IOS 4.2 on my iPhone from there. I plugged my iPhone back into my MacPro to see what would happen. I got an error message saying "This iPhone is not compatible with this version of iTunes, please upgrade". Well...I don't want to upgrade. Because I hated iTunes 10 with a passion. Now I also notice that my iPhone's bluetooth is broken with IOS 4.2 and my Subaru. So I'm being forced to upgrade to an iTunes version that I don't want and my phone isn't functioning correctly. I'm going back to what I had.

I loaded the 4.1 firmware (it's out there) onto my MacBook and did an Option-Click on the restore button in iTunes 10. That let me navigate to the 4.1 firmware file. It connected with Apple, wiped the phone, and reinstalled the older firmware. When it came to the point after rebooting where it asks if you want to set it up as a new phone or restore it from the last saved backup...I simply quit the process and ejected the phone from my MacBook. I then connected it to my Mac Pro and did a restore from iTunes 9.2.1 because that's where all my contacts, Apps, etc. where.

My phone is now exactly where it was before upgrading.

Ahhh...you must have had the old SHSH blob backed up on your MacPro. This I've heard of. Unfortunately, I didn't know about it prior to updating to 4.0 with my old 3GS, would have been useful at the time. I'll be sure to do that with my current 4.1, should I decide to update to 4.2.1. Thanks for the info.

Yes, after upgrading to IOS 4.2.1, my iPhone4 doesn't make it past 5 hours of minimal use. Is there a way to roll back the upgrade? I can do without AirPrint and AirPlay if it means my battery will last longer.

This battery drain does exist, before the upgrade it was fine, after the upgrade, 10% battery drain every 15 minutes, even when the phone was idle (I first noticed it when i started using the MSN Live messenger app, 35% drain after a full charge in 20 minutes)

But I think Lawrence Finch is right, it's nothing to do with which OS you are using as it did on my old 3GS when I upgraded once as well.

So I took the advice on this thread and tried to isolate the problem. With my iphone 4 is was Email push services that was causing the drain. I did a complete restore through itunes and set it up as a new phone, manually downloaded all my apps and synced all my music and vids. Turned wifi back on, left location services and 3G off as I never use them any way.

The only thing I did different was to leave my email account alone, I never set it back up, so no email push or account set up.

Now after a full charge last night at 11pm, the usage is 26 hours on standby with 1 hour 45 minutes of usage and the battery is at 84% so it seems to be the push email which was causing it.

I'm gonna set my email account back up now and see what it does, I'll let you guys know how I get on

It's a problem that has been around since Push became available. What happens is the email app loses a connection to the server and opens a new one. But it continues to try (fruitlessly) to connect on the old connection. After a while there are a lot of old connections, all using power and none accomplishing anything. Restoring as new kills all of those old connections, so if you restore the Push account it should be OK.

Sometimes the problem can be fixed by just deleting the push email account, rebooting, and adding it back.

After I upgrade tthe new ios4.2, the battery drains so fast. I want to go back. I shouldn't have upgraded it. So regretful.

i too did the upgrade and noticed the battery draining real quick; So i dug around here and found someone say to reset the phone ( settings, general,reset, reset all settings)so i did this and i also read here to reset the iphone to factory setting after u have plug it in and did a sync. i said what the heck, what do i have to lose but time; GUESS WHAT! That fixed my battery drain problem: today i unplugged my phohe at 630am, it is now 952pm an i am at 50%: so this did work for me: prior to the upgrade my battery was fine: it seems to work for me: now can someone help me with my home button working then not working..thanks dm atlanta ga

Me too. Upgraded to 4.2.1 and the battery started playing dead. A clue was when I ran iSystemPro. The Processes page indicates the CPU load. With Notifications turned on, the overall system load was about 60% continuously. Turning notifications off now shows less than 10% which is normal. I have no clue which of my ten assorted applications that are using Notifications is the culprit but I plan to investigate. Any app that shows CPU usage should work.

Argh. Things are not going well. I enabled Notifications, went through every single application I had that uses Notifications, and turn off Sounds, Alerts, and Badges. In this state, CPU usage was about 10%, which is great. If I turned on ANY application that uses Notifications, the CPU usage climbs to about 60% and stays there. One would think that with 10% CPU usage, the battery drain would be normal. Nope. It drains the battery equally fast with either 10% or 60% CPU usage. I can sit there and watch the battery percentage go down. So, CPU usage is not the problem. My apologies for the false alarm.

After the 4.2 update I noticed a rather fast battery drain. Conducted a test with phone at 100% and set to airplane mode with 2 applications running .. settings and an app that monitors cellular data usage. 70 hours later phone showed 15% battery remaining. This had never happened so fast before with 4.1

Yes yes I just posted something about that one minute ago. It's draining soooooo bad on mine too.

Mine drains fast too. I did a hard reset after the upgrade and that didn't help.

Settings reset from the general options menu, worked for me. (normal reset, no content reset).
Didn't lose anything, just had to reconfigure wi-fi and general options, alarms etc.

100% still after 6 hours.

iPhone 3G, iOS 4.2.1

Have you tried the mail trick? If you have Push email accounts, go to Settings/Mail,Contacts,Calendar. Tap the name of the Push account and turn it off (Turn off the account, not push). Next open the mail app, verify the account is gone (and let the mail app know it is gone). Exit mail and reboot (hold HOME and SLEEP until the Apple logo appears). Turn the mail accounts back on. So it sounds a little less like magic what this does is force stale Push connections to close. For reasons that aren't clear if a connection stops working the phone opens a new one, but continues trying to connect on the stale connection(s) thus using battery to no purpose.

Did you do this exact test with 4.1? Not sure which cellular data app you are talking about, but Dataman is a very heavy battery drain (despite claims to the contrary by the developer).