i think youve mistaken b/c there is no such 2.0.4. it went from 2.0, 2.0.1, 2.0.2, then to 2.1.
and the process is simple, for windows xp/vista, download quickpwn 2.1, iphone 2.1 firmware and 3.9 and 4.6 bootloaders then in itunes restore your iphone to "stock 2.1". after its restored it will ask you to activate. so thats good, then you open up quickpwn 2.1 and plug in the iphone then it will ask for the 2.1 firmware file, select it from your desktop or where ever you downloaded it to. then it will ask for the bootloaders, so find them and add them, then it will go ask you to check off cydia, installer, and unlock (also change bootlogo but i left this uncheck) make sure you check those 3 in particular or else **** will go wrong, and your phone will NOT be unlocked. then just follow the instructions given on how to get into DFU mode and the rest is golden.
thats pretty simple - and this will only unlock a 1gen iphone NOT 3G.
and for mac: i dont know
