There are no known issues, so we'll need more info to diagnose what's going in your case: What MP and flight firmware versions are you using? What OS?
I have the mission Planner 1.1.62
The firmware version is the latest that I could load with the mission planner today.
OS is Windows 7
because I read in an other thread that the USB could be broken. So i tried the serial connection. but from now the RX and TX LEDs are flashing wired even If i have not connected an USB cable.
I have done the following:
5V from Iphone power supplay via the USB cable to the micro USB of the APM 2.5.
UART 2 RX TX and GND over USB to serial converter to the PC.
I think the there was a GND loop over the power suply of the notebook and the powersupply of the 5V (Iphone) so that there is somethink broken???
It must work a little bit at least because I can burn a new firmware!!
thank for the help
Franz: Your problem is that you are using a VERY old version of the Mission Planner. The current version is 1.2.11. Please upgrade to that here.