Here you go - this is a complete 2.4 (220.127.116.115512) install that includes my modified version of the Decent skin (modified for 2DIN headunits) as well as my US English TTS voice package. Just extract this archive to a blank SD card and then copy over you content files (content/building, content/dem, content/map, content/phoneme, content/poi, content/scheme and content/speedcam) and maybe you sys.txt file (you can try my version, but no guarantees!).
You'll also have to "direct" your headunit to the nngnavi.exe binary (or rename it to what it was on your original SD card). once Primo is running, I'd recommend going into the settings and selecting the Decent 2DIN skin - it's a much improved skin compared to the stock skin.
Here is a link to the complete 2.4 archive: [Please Register or Login to download file]
Here is a link to the Decent 2DIN skin thraed that I just posted today: Decent 2DIN skin
Let me know if you have any questions or issues.