Tiny6410 MAC Address resets after few days

Hello,

We are using 10 FriendlyArm Tiny6410 boards(WinCE6) in a network.
We assign unique MAC & IP address to each board, but after a few days the
MAC Address is reset to default value(e0-aa-c8-de-63-52).

When MAC Address is viewed in Tiny6410, it shows invalid value (e.g.
"02--0-0--00--0-0-" for the board which was assigned "02-00-00-00-00-F2" as
MAC address) (see picture)

Is there any solution to this issue ?

Does the board also lose its unique MAC address if you re-boot the board?

Does the mini6410 use the DM9000 ethernet chip?