Strange situation after cloning 2nd hdd

Hi,

A friend of mine screwed up his hdd install and asked me to help.
As we had his eeprom.bin and a fully installed/configured hdd (mine), I chose to clone it.
All worked out fine, he could access internet, ftp connection with my pc no problem -> cool!
But! A FTP connection between my xbox and his xbox could not be established. Also systemlink does not work! We can see eachother, but connecting is a problem.

I (and he) run xbmc dashboard on a softmodded xbox.

This is what I've done.
- Cloned his hdd with my hdd (same size) using xboxhdm 1.9
- Locked his hdd with HIS eeprom.bin
- Replaced his hdd in his xbox, working fine!
- Cleared tdata/udata map, set the clock, change the ip settings and network name.
- Still problems between the two xbox connections.

Strange thing is that, when looking at both our system settings, the mac address is the same!
As this kind of information (including ip, zone, video settings etc) is stored in the eeprom, how could this have happened? I always thought that the macaddress is a hardware variable.

It looks like it that our xbox's load the eeprom off the hdd (causing the macaddress being the same), is this possible? Can some softmods do that?

Note: My xbox was already softmodded when I bought it, running XBMC when booting.

Cheers and thanks in advance,
Martijn