Before starting the explanation part, here is some short info: the test subject is Citroen C5 mk2 (facelift) , radio - RD4. AUX and CD changer activated.
Perhaps, in internet you already found many topics how to set up or update that particular stock MP3 reader made for PSA.
How to connect and activate that module via LEXIA should be available online. Here I`ll try to give some collected information about firmware, and some other tips that maybe can be in some help.
Here, you can find original VAG 1.9 TDI AVQ engine EEPROM files.
Here is the story: I use my cellphone as GPS navigation unit most of the time in my car and unfortunately it GPS chip do not get so fast satellite coverage, or either I need to turn on the 4G network on for fast location.
As “bonus” the back of the phone get hot. Also, sometimes due the navigation process and heat from the car vents phone get fast hot and start loose control.
Next, I try to use my old Nokia LD4W Bluetooth unit and via right GPS sender app my android phone start to work better.
After that, seems become dependent of the battery of that Nokia unit so I bought few parts and create “proper” car GPS sender.