Q: Error 1015 while iPhone 3G restore

Has your iPhone ever been jailbroken?  It sounds like it has.

Unauthorized modification of iOS can cause security vulnerabilities, instability, shortened battery life, and other issu…

The terms of use of the Apple Support Communities forbid us from offering any advice for jailbroken Apple gear.

You're on your own.

No, you won't get any support from Apple for a jailbroken phone - it voids the warranty on it and as the 3gs is a very old phone now, consider just ditching it and buying a new phone - does not have to be the latest model, but you could pick up a 5c or 5s more cheaply now the 6 and 6+ have been released.

Normally, if you try to restore or update a jailbroken device, then it will revert to being locked again and if you want it unlocked, then you need to do it properly and not by jailbreaking it.

Other than this, nobody can help and Apple will not help you with any jailbroken device because it voids warranty on it.

As you have been repeatedly told, you cannot get any assistance here

or from Apple for a jailbroken iPhone. Asking the same question in a different

manner will not change the answer.