Changing MAC address on the Fly
 

I'm doing some research on old kernels and running the following on 2.6.7 or 2.6.8 gives a resource busy error. But on 2.6.28 the command works as expected. How would I determine which kernel allowed this command to change the mac address on the fly? ip link set dev <dev> addr <MAC>

You can see some screenshots in the attachments. Thank you!

Normally you should bring interface down when you change some interface parameter.