Tweak HU-1205

Somewhere on the internet I read that the HU-1205 can be tweaked. You can tweak the navigation system so the destination can be adjusted while driving
and you can tweak the sound settings for, maybe, better sound quality. Unfortunatly they did not mention how you should tweak those settings. Does anyone know how to do this and do you have any experience with it?
Thanx MDN
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.