The main dashboard module has a free 6-Pin Connector.

Adapter by Peugeot
Adapter cable with 6-pin connector on one side and USB female on the other: part number 6574JH for around 20 Euro at Peugeot dealers.
Pinout
The Pinout of the connector (MQS generation II) is as follows:
USB CONNECTOR
. . . . . . . . . 6 | o o | 3
. . . . . . . . . 5 | o o | 2
. . . . . . . . . 4 | o o | 1
O O O O
^ ^ ^ ^
| | | |
| | | - Blue Antenna Connector (GPS)
| | |
| | - Purple Antenna Connector (GSM)
| |
| - Grey Antenna Connector (FM 2)
|
- White Antenna Connector (FM1 / AM)
Pinout (according to PSA documentation) :
1 - Reserved
2 - Reserved
3 - +5V (red cable)
4 - GND (black cable)
5 - USB Data - (white cable)
6 - USB Data + (green cable)
Note: the colors of the cables are the standar used in USB cables, but they could be diferent.
This kind of connector is widely used by PSA for a lot of purpose (warning, auto AC, …). But for some usages, only 3 pins are present on the connector. In this case, you have to buy 2 of them to have one usable for the USB.
Instructions:
Just connect an usb flash drive according to the pinout!
DO NOT REVERSE THE +5V AND GND OR ELSE YOU COULD DAMAGE YOUR USB FLASH DRIVE OR EVEN THE RT4 SYSTEM.
(reversing the data pins caused no problems in my RT4, but be advised that you are at your own risk!.)
It is recommended to use an USB flash drive with a read/write access led, so you can visually check that the system is reading or writing data from the flash disk.
Have you connected the USB port? go on to the Customized Upgrade Scripts
USB conectors pinout:
http://pinouts.ws/usb-pinout.html
Some pictures by coolman_kk:
(click to enlarge)





