How can I see the MAC address of the box in the firmware?

There are several options for how to do this:

  1. Install  ‘Extra Tools’ and ‘Extra tools info’ plugins from the repository.
    After restarting enigma2, the menu ‘Extra tools’ will be available in the context menu by going to the menu go to Mediaacenter info >> Ifconfig and clicking on the ‘OK’ button will get all the information on the network adapters (including the MAC address you need)
  2. At the command prompt (telnet), run:
ifconfig

You will see extended information about network adapters, including MAC address:

eth0 Link encap:Ethernet HWaddr 00:16:B4:06:AD:40 
inet addr:10.10.10.7 Bcast:0.0.0.0 Mask:255.255.255.0
inet6 addr: fe80::216:b4ff:fe06:ad40%lo/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:24636 errors:0 dropped:68 overruns:0 frame:0
TX packets:8389 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000 
RX bytes:11055359 (10.5 MiB) TX bytes:902475 (881.3 KiB)