My issue was the “1015” and this fixed it.
If you updated your iPhone 3G to iOS4, you probably noticed how slow it has become. Simple tasks such as dialing out and taking pictures have become painfully slow but this can be fixed by downgrading back to 3.1.3! Also, if you keep getting error 1015 when restoring your iPhone 3G, follow this guide to fix that issue. The video is detailed step-by-step so you don’t get lost in the process.