Emergency call screen issue?!

[dark3lf1337]

Hello all.

I recently bought a used iphone 3g 8gb off of ebay (locked), with hopes of jailbreaking it, then unlocking with T-Mobile. Problem is, when I turn it on, it just says "slide for emergency", and that's all i can do: I can't get to the springboard or anything. Also, when I insert my SIM card from my old t-mobile phone into the iphone, itunes says that the sim is not supported, obviously because it's t-mobile and I have not jailbroken and unlocked yet. And I can't do either of these because I can't get past the emergency call screen! Please, reply if you have a fix. Thanks in advance!

~DETAILS~
Firmware: Unknown - can't figure it out because I bought it off ebay and it didn't say, and I can't figure it out because I can't get past the emergency thing, blah...
Baseband: cant figure it out, same reason as above
Model: 3G
Size: 8GB
Computer OS: MAC OSX

Hope this helps!

[Cer0]

Can try a custom firmware to hacktivate/jailbreak/unlock it.

To do that we have guides in the guide section. On the right side of the page chose your device and pc OS and it will narrow it down to the guides for you.

Apple, iPhone, iPad and iPod Guides | ModMyi.com

Newest guides are at the top.

This one may be of help. How to Jailbreak/Unlock 3.1.3 iPhone 3GS/3G/2G iPod Touch 2G/1G with PwnageTool OS X

[grant1x]

all you need to do is get a friend wit an ATT sim card to bypass the screen.
or buy a phonebook SIM card from radioshack and put it in then take it out once you are at the springboard.

[dark3lf1337]

Since I don't know/can't figure out what the firmware version # is, is it best to just restore. Will that help?

[Cer0]

If you restore it will still be on the activation screen. So build a custom firmware and restore with that.