Jailbreaking advice

[Origommi]

OK... So I am new to Jailbreaking and need some expert advice. Got my iPhone 2G - 2.2.1 off ebay. The guy I got it from said no worries if it starts acting up (freezing, problems booting up, download the new firware through ITunes by accident etc) simply open the link (BELOW), follow the steps and it will be ok. Just wanted to run it through you all before I end up with a brick. Please let me know what you think. Will this way of unlocking/jailbreaking fix pretty much any problem I cause as long as I restore? Thanks for the advice.
iClarified - iPhone - How to Unlock/Jailbreak Your 2.x.x 2G iPhone Using QuickPwn (Windows)