How to install debian 4.1 into Pogoplug Pro/v3 from openwrt? (no replies)

My pogoplug pro/v3 alreay flashed with openwrt.
I read the post from http://forum.doozan.com/read.php?2,23630

Oxnas plugs

Latest Linux Oxnas kernel and rootfs (sticky thread)
Latest Oxnas u-boots (sticky thread)

But I don't know how to flash it to latest 4.1 debian kernel and image.

Is there any tips for my box?

Thanks!