Car Stereos & iPhone iOS 4.3.+ problems? This might help...

After upgrading your iphone to iOS 4.x (from any older version) you might notice that your car stereo or Pioneer Home AV system isn't supported device anymore. This is a bug on iOS system and I think that there is a solution how to fix it pretty easily. Just go to Settings -> General -> Reset -> Reset All Settings. This wont erase any of your personal data, but it will erase all the system settings and also pairing information of the devices. This pairing information might be the reason for this whole mess, because after the update iPhone doesn't have same fingerprint anymore than it used to have and thats why your car stereo doesn't want to connect.

This fix works with Pioneer AVIC- and DEH-Series and some JVC's also. Might work with all others too.

Just remember, if you restore your previous backup after you have resetted all the settings, you will end up with the same connectivity situation again. Hope this saves someones day... it sure saved mine.

How about going back to old version? Well, it seems that you dont have to but if you really want, you should have though this before you update. Because Apple doesn't allow downgrading anymore. Key to downgrade without asking from Apple is SHSH Blob file that should be saved from iphone at some point. Read more from here if interested: http://en.wikipedia.org/wiki/SHSH_blob