Is it TRUE that an iPhone cannot be "Bricked"?

Because I think I've done it.

I hear people say there's always a way. Maybe you can help me out here, because I've been stuck for two weeks and haven't asked a single person for help.

I've got the 1st Generation iPhone and I'm armed with a MacBook Pro, 10.5.6 and PwnageTool.

WHAT: I was getting the endless reboot to the Apple logo, so then I restored it (from the General settings menu on the phone) and it worked again... At least, for a little while. Then I tried to sync it or something and it went right back to the looping thing.

So instead of restoring it again, I went to iTunes and reset the whole entire thing. Now it's asking me for a SIM card, so I stuck in a random ATT card, but iTunes wants a social and zip code. So I got pwnagetool but I cannot enter DFU mode. I has fail! i need zune! The phone just keeps turning on an off.

So I showed my friend who also has an original iPhone and he was like "I can make my iPhone do that! Watch, you just hold the Power button and it restarts over and over! Your button is stuck!"

HOLY SHIT! HE'S RIGHT!
So I bought a new backcase with the headphone jack assembly in it, but it still does it! My iPhone thinks that I'm holding down the Power button. Evidence of this is when I hold the home button, it powers down as if I was holding the home and the power button.

Am I bricked?

have u tried a dfu restore?