My friend is enrolled in the iOS developer program and he has offered to add my UDID to his account. My question is, after he adds my device will I be able to install iOS 7 without access to his account (his username and password). Like can I just download a copy of iOS 7 from another website and then use that? For example, this would be possible if Apple just did server side authetication of the UDID. Or does Apple actually change each iOS download binary to specifically tailor it to specific devices?