So I used "f0recast" to figure out if I had an old or new boot rom and it turns out that I have an old boot rom. I am on iOS 4.0 and have never jailbroken/unlocked my iPhone. Since I do have the old boot rom, is it safe for me to jailbreak/unlock my phone using PwnageTool 4.0.1 or should I wait? FYI, I did as much research as I could on my own and searched the other threads to find someone in the exact same scenario as me. Hope someone can help me out, thanks!