I hope someone will find this useful. You will need Terminal app already installed.

Launch terminal.

To check your current mac setting type:
ifconfig

You will see sth like this:
lo0 : ... - this is unimportant
en0: flags= 8863 <UP,BROADCAST, ... bla bla bla
and finally ether xx:xx:xx:xx:xx:xx

where: en0 is wifi's network interface and xx:xx:xx:xx:xx:xx is current mac address setting.

To set new mac address for your iphone's wifi card type:
ifconfig en0 lladdr yy:yy:yy:yy:yy:yy

where: yy:yy:yy:yy:yy:yy is new mac address.

After rebooting iphone mac address will return to factory setting.
This method has been tested with firmware/bb 1.0.2.
The new mac is included in packets send by iphone.

Cool....

I need to spoof a mac address on a very regular basis but always to the same mac address.

I am basically spoofing a iphone mac address to be an ipod touch ....

Just to confirm do mac addresses have any checksum or is any format valid, Basically a mac address for an ipod touch always starts with 00 1d 4f, can i put anything after 00 1d 4f ??

How would i script this so I would only need to type ./changemac from terminal or better still how would I add a shortcut to the main springboard to changemymac to the one I embedded in the short cut.

Matthew

Considering the mac format:
You can use any sequence of 6 bytes as a mac address, however the first three usually denote the producer of the network adapter. As a consequence some routers may not accept non-standard addresses[like 00:00:00:00:00:00]

[NEW!] nicer script
I suggest using "mac" name for it
Usage:
mac - shows your current mac address
mac xx:xx:xx:xx:xx:xx - sets mac to xx...

Script code:
#!/bin/sh
if [ $1 ] ; then
ifconfig en0 lladdr $1
else
ifconfig|grep ether|cut -d" " -f2
fi


You can grab it here:
http://singaja.googlepages.com/mac

Put this file to /usr/bin [using iBrick on PC/ independance on MAC]
Type chmod +x scriptName


A native application with GUI wrapping mac changing would be nice. However I cannot currently develop iphone software in Win32 environment[or can I?].

@Singaja

Can you make a script that we can type the desired mac address into before installing so that it will just change the mac address when ran instead of needing to enter the desired mac address everytime?

You can simply replace the $1 with the mac address you're looking for -
This way you can just type: mac set
and it will set the mac address of your choice.
so the script will look like:

Code:

#!/bin/sh
if [ $1 ] ; then
ifconfig en0 lladdr xx:xx:xx:xx:xx:xx
else
ifconfig|grep ether|cut -d" " -f2
fi

Thanks to Singaja for posting this

@Adsum

[current path is irrelevant]
type in the terminal :
echo "mac your:desired:address:typed:in:here">>/private/var/root/.profile

If would like to disable or adjust auto-mac-setting in the future then delete or modify the line mac bla:bla:bla:bla:bla:bla in /private/var/root/.profile

Thanks Singaja and Tecknix! Tried both methods and both worked. Nice to have options.

One would want Tecknix's method if they wanted to have the mac address reset after restarting the phone and Singaja's method if they wanted the new mac address to stick even after a restart. I did have to restart my iPhone before the .profile method worked (checked using mac script in terminal). I don't know, but that may be because I used WinSCP instead of terminal.

@Adsum

I should have mentioned that. It was meant to work after a restart. The .profile is a kind of autorun thingie u have on windows for instance. Technically the content is run when you login using root account , which happens when you turn your phone on[and also when logging on phone's SSH-server presumably].

Singaja,
Do you know if setting the mac address for the phones that lost their wifi 'no wifi' would help solve the problem?

I don't have a phone with that problem right now and would like to know what everyone's take is on it.

TeckniX,
Definitly not , the no wifi is clearly a firmware problem[baseband firmware to be precise]. A similar problem happened to me when I was revirginizing my phone. Something went wrong[not sure why] while flashing the baseband and i needed to start the whole process over. When the baseband was corrupt i had the no-wifi problems which others report[In the settings for instance you cannot enter the wifi section]

Changing the mac address of the wifi adapter won't do any good when the driver is corrupted[or non-existant at all].