After much searching, reading, testing and failures; this worked for me on Armbian.
Create /etc/fw_env.config with:
/dev/mmcblk0 0x3F8000 0x8000
Ensure good settings by running fw_printenv, ensure no CRC error.
# fw_printenv
arch=arm
baudrate=1500000
board=evb_rk3328
board_name=evb_rk3328
...
Set new MAC address using fw_setenv
# fw_setenv ethaddr {new MAC}
Reboot, confirm MAC address with 'ip link'
I tried using the Windows tools to much failure. Once I put in good fw_env.config settings standard tools under Linux "just worked".
Happily removed udev rule, no need for extra setup in /etc/network/.
