I have a 3G iPhone. It had been activated with AT&T SIM and running v3.1.2, then jailbroken and unlocked via blackra1n + blacksn0w and working nicely with my T-Mobile SIM.

I then did an accidental upgrade to v3.1.3.

I've been able to do a restore to v3.1.2 and re-jailbreak via blackra1n + blacksn0w without having a SIM installed. No unlock to work with T-Mobile of course, but I can live with that for now.

My problem now is that Push and YouTube don't work. As I understand it this is a "hacktivation" vs. "activation" issue. I expect blackra1n + blacksn0w "hacktivated" the restored v3.1.2. I understand that there are extra steps that I can take to make Push/YouTube work with a hacktivated phone.

However, if I can borrow a friend's active AT&T SIM card, is there a way that I can do a "real" AT&T activation at this point?