Help withJailbreaking iPhone 4 on 4.2.1

[BlazeShaman]

Hello,
I have recently received an iPhone 4 (4.2.1), and I am very much wishing to jailbreak it.

Can anyone help me with this? What program would I use to do this, please? Are there any downsides to jailbreaking this?

Thank you for your help.

[z6joker9]

Yes, the downside is that the jailbreak is currently tethered (you must hook it to a computer to boot the phone if it gets powered down or rebooted).

Do you now or will you ever need an unlock (ability to use it with other carriers... applies if you are on AT&T and might switch to T-Mobile one day, etc)?

If you need an unlock or think you might one day, I would hold off as the process is involved.

Otherwise you just update through iTunes as normal, and run redsn0w to jailbreak. Remember you'll need to run it every time you want to boot the phone, so don't let it run out of batteries while you are out.

[BlazeShaman]

Yeah, my iPhone came already updated to 4.2, and my carrier (Vodafone) offers a free unlock should I need to switch carrier.

Thanks for your help.