Wirelessly posted (Mozilla/5.0 (iPod; U; CPU iPhone OS 3_1_3 like Mac OS X; en-us) AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7E18 Safari/528.16) I have a iPhone 3g firmware 4.2.1 (8c148). I have been trying to jailbreak to change carrier to t mobile. Downloaded redsn0w and firmware but the firmware I got cannot be recognized. Have tried other firmware downloads but they never come as .ispw file so redsn0w won't recognize. I am using windows 7. Baseband is 05.15.04. If anyone can help me I will greatly appreciate Ps. Tried greenpoison too and all it does is tell me to try again and phone needs to be restored.