I don't usually use my blog to deal with tech-type-stuff, or to help anyone in any way.
Today, I thought I'd change that... Just for today...
This post really only concerns seasoned iPhone jailbreakers who are having issues with their 4.1 upgrade... if that isn't you, you probably just want to bounce up out of here.
This is apparently a pretty widespread problem, and I seem to have found the fix... I'll warn you now, it's fairly labor intensive, and it requires a pretty good grasp of the inner workings of your root folder, or just plenty of free time to google the steps you need to take. I'm not going to break down HOW to do it, just WHAT you need to do.
I'm running iOS 4.1 on my Iphone 3G- it was running slow when I first upgraded, and I had an issue with the proximity sensor not recognizing when the phone was away from my ear during a call- basically, the screen would go black when I was on a call, and not light back up when I took the phone away from my face- which meant I couldn't hang up on anyone, and I'm ALL ABOUT hanging up on people, so I had to correct this IMMEDIATELY.
I heard rumors that the proximity sensor issue & speed issue could be resolved by a factory restore AS A NEW PHONE, but I didn't want to lose all my contacts & what-have-you-
Here's how I got everything running smoothly...
I backed up my contacts, calendars, safari bookmarks, & KEYCHAINS (remember that for later) manually via SSH (i use Fugu), cooked my own custom jailbreak firmware with PWNAGETOOL, restored as a new phone with my cooked OS, and the phone seemed to be running faster than it EVER did running 3.1.3. (Battery life also improved). Then I SSH'd into the phone to put back all the files I saved earlier.
I'll spare you the details, but suffice it to say, everything worked fine, until I restored my KEYCHAINS files, at which point the proximity sensor issue started up again.
I was forced to factory restore AGAIN, with my same cooked firmware... this time I replaced only my Contacts, Calendars, & Bookmarks, but NOT MY KEYCHAINS.
I just re-entered that info manually, which was a pain, but it somehow did the trick, as I am now running a fully functional jailbroken version of iOS4 on an iPhone 3G with NO ISSUES WHATSOEVER regarding speed, battery life, or proximity sensor issues.
AT&T's service still sucks though.
Nerdy enough for ya, guys?