f you had your iPhone 3G unlocked and jailbroken on the iPad baseband (06.15.00) and updated/restored into iTunes and you got the 1015 error code, then follow this guide to get your iPhone running in no time.
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NOTE: YOU HAVE TWO OPTIONS, first is to follow THIS guide and fix your iPhone 3G, the other is to downgrade to ios3.1.X with my other guide (link below) and fix the iPhone....Downgrading is a much BETTER option as it will make your iPhone 3G way faster and its much easier to do. If you're lock/home button is/are broken then you have no choice but to downgrade.
https://www.youtube.com/watch?v=y39hPYLPAN4Click on the link above ^ to downgrade to 3.1.2 or 3.1.3 ^
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Download links: (All of them are available at the website below)
http://ihelpcorner.com/how-to-fix-error-1015-for-iphone-3g-model-a1241/