Answer
From release 10.140.0.12 there is an easy way to set the MAC addresse for the two Ethernet phys on the 60-SOM and the IG60.
The command is called "mac". Please see example below:
# mac
Eth0:
Eth1:
# mac --help
usage: write: mac [-f] [xx:xx:xx:xx:xx:xx]
read: mac
# mac -f 11:22:33:44:55:66
Eth0: 11:22:33:44:55:67
Eth1: 11:22:33:44:55:66
# mac
Eth0: 11:22:33:44:55:67
Eth1: 11:22:33:44:55:66