Works, but why so complicated?
Before updating unlaunch have a look at the Release Notes
http://problemkaputt.de/unlaunch.htm (scroll down a bit) to see if you are interested in the changes for v1.9/v2.0.
Put
UNLAUNCH.DSI on your SD and start unlaunch file menu by holding (A)+(B) when turning on the DSi. Scroll down the list until you find the entry "
UNLAUNCH.DSI" or "
Unlaunch DSi Installer". Simply run the installer.