I have been looking around for a way to change the mac address on my 3gs running 3.1.2. I have tried the following to no avail:

From root (su root + correct password)

ifconfig en0 lladdr yy:yy:yy:yy:yy:yy
ifconfig en0 ether yy:yy:yy:yy:yy:yy

I have found some information HINTING at the fact it only works with the 3g, and not the 3gs. Other information hinting at it only works under 3.0 and not 3.1.2

Can anyone shed some light on this? A little bit more information then "That combination can't do it" as I have a touch, and a couple of 3g's (well members of my household do), and may consider downgrading to 3.0 if that's the issue.

Thanks in advance.