Fix MAC from Linux

NOTE: Altering your MAC address may result in a different IP address being assigned, and conflicts on your network.

NOTE: We recommend using the MAC address that was assigned to your 4Kopen board at all times (look for a sticker).

If you find that your 4Kopen board's MAC address changes on each boot, then it may be necessary to re-program it.

A symptom of this is that the board's IP is different each time it boots as well.

You should be able to locate your MAC address on a sticker on your board - it should be six groups of two hexadecimal digits (0-9, A-F).

On the 4Kopen board, the MAC address is stored in the SPI flash, which can be updated using the following command:

printf "ethaddr=11:22:33:44:55:66\0" | sudo dd of=/dev/mtdblock0 seek=851968 oflag=seek_bytes

NOTE: The printf "\0" is necessary to ensure that the data is terminated correctly

Confirm with:

$ dd if=/dev/mtd0 skip=851968 count=26 iflag=skip_bytes,count_bytes status=none | hexdump -Cv
00000000  65 74 68 61 64 64 72 3d  30 30 3a 30 30 3a 30 30  |ethaddr=00:00:00|
00000010  3a 30 30 3a 30 30 3a 30  30 00                    |:00:00:00.|