I assume that's normal since the DS doesn't really need to display anything if it's just being used as a controller and if you don't interact with it when you first start it up, it may decide to blank out the screen to save power. So once you have the IP settings configured and such, what it displays on the DS screen is no longer important since all the interaction is now taking place on the computer.
I vaguely recall playing around with DS2Key awhile back, but it was the USB version that worked with the slot-2 device that the N-Card I used to have came with. The N-Card had this nifty little slot-2 cart with a USB connector. It was mainly used to transfer files to/from the N-Card's internal memory (since it did not use a external MicroSD card like most flashcarts use today). But it also had this open source homebrew app that allowed me to connect it via that slot-2 device as a USB controller of sorts. It's too bad no body made anything interesting with the source code behind that USB device. For example it would have been awesome to use that USB slot-2 cart to transfer files to other flashcarts that use MicroSD instead.
It would save me from having to wear out the sd card slot from removing/inserting the MicroSD card every time I wanted to put a new game on or something. Not to mention it may have been possible to use it as a video in device so you can have a computer send a video direct to the DS screen. There was an old GBA TV tuner that did something like this, so it's definitely possible. Without it, the only other way it could have been done is through WiFi which is just too slow on the DS to be usable for video streaming.
I have long since given it away though since the internal battery broke off and now it's not really safe to save games on it anymore. The battery backed save chip was just a stupid design decision by whom ever made that card. Otherwise it worked great. It's too bad the N-Card is impossible to find anywhere though.
EDIT:
Oh damn. Completely forgot how old this thread was...
