I made this firmware for myself, and shared with community, if you don't like , don't use.
And you have to eat your hat as I managed to stuff all the necessary OpenWRT packages into 2MB flash of ASUS WL-700GE which has internal storage with IDE interface. So 4MB flash is massive space especially if there is USB ports on the router where you can just plug in external storage.
http://wiki.openwrt.org/ru/toh/tp-link/tl-mr3020
2.5 Mb is not enough for that.
This is offtopic, so we must stop i think.
P.S. If you can do it better - share your build with community. Target mr3020 without usb storage.
First we should be thankful smit shared his. Considering he did it on his own dime... that is saying something about him. I wish I had one to try it on now.
The tplink nano is very capable. Look into Avalon 4.1's. They ran special ddwrt with gui as a controller(it loses router wifi and such just runs cgminer). The usb port you hooked the miner up to if 1 or a hub if multiple. So you are not giving this tplink enough credit. I would agree with Smit if you have better release it.