The next thing was to add an LED backlight because the display isdifficult to readin the sun.
Unfortunately the firmware is not the best choice. But since it has an AVR Mega as main controller, there are a couple of alternative firmware projects for this remote control. I decided to put "er9x" on it. All I have to do is to solder an ISP plug on the right pins of the controller and take my AVR JTAG ICE3.
The FlySky TH9X is a relative cheap 8 channel 2,4GHz remote control. I payed 80 Euros for a brand new couple of a receiver and the transmitter.