Jailbreakme.com? for 4.2.1 ipod touch?

ok ive did it before but i had to reboot it but thats another story now my ipod touchs pic apps n jailbreak r deleted now i have a 4.2.1 ipod touch n i looked up the website n it said this Welp. verison too new you need to downgrade to 4.0.1/3.2.1 or earlier ( which may be impossible, explantion) before you can use this site Mre info >> and usally it lets u slide n it's that easy but now it wont let me i looked @ more info n there's nothin so wat do i do?