Title: [Microsoft] Hack MN-740 to tal DGL-3420 firmware
I *thought* that D-Link DGL-3420 package looked awfully familiar...
Basically, what you do is, get yourself the MSBNDownload.exe updater, then apply some modified catalog files and a "new version" firmware to it ("01.00.02.0022"). This "new version" firmware is actually a slightly tweaked version of the DGL-3420 firmware v1.01.
MSBNDownload happily blasts the DGL-3420 firmware into place, then checks for the "updated" MN-740 and says "oh no, I don't see an MN-740 anywhere! I must have failed!" (You might want to have it retry, once more, to make sure that it doesn't see an MN-740. That means the flash most likely succeeded!)
At that point, manually set the IP address of the unit you have connected to something in the 192.168.0.x range, then connect to http://192.168.0.30 - and voila, you'll see the DGL-3420's web-based interface. Reconfigure the unit (IE works best :P imagine that!) and you're set to go!
One person at the end of that thread complained of having an MN-740 unit that claimed to have firmware "01.00.02.0026" in it. I suspect that if you renamed the new firmware to be .0027, the same procedure would work, but I don't know - mine was .0021 when I started.
I understand it still works with an Xbox too, but I have pretty much given up playing games on those anyway...