Restore without losing my AT&T acivation?

[Ohs0flyMar]

I have an iPhone 3g 3.1.2 jailbroken running on tmobile. As most know when you jailbreak on 3.1.2 without an offiial At&t activation.. Your push notificaons will not work correctly. The push fix in Cydia isn't an option.. It simply misses too many messages. I activated with a friends At&t Sim card before so I could get them working. But my phone is moving kinda sluggish and I want a fresh restore..but icant get the sim card.. So is there a way to basicly restore and delete everything without losing activation?

[shadow25]

Look up the Dev Team Push fix, and nimble your certs.