Hallo!
I am sorry to upset you, and I had absolutely no intent to disturb or confuse. I thought this was a good topic to continue. As even if it is old it is apparently relevant as the only source of this information on the whole Internet.
For my bad German, I would appreciate a translation effort to add to the knowledge base of the forum. I can read with almost no effort, but to write is very hard.
For future reference, here we go:
-----------BACKGROUND INFORMATION ------------
When performing an update two things are needed:
FIRST
Two files are put on the SD card by the Multiplex Launcher. This can also be done with an SD-card reader and a computer, or directly in the File Manager when the transmitter is in USB mode.
COCKPIT_C3.bin . NOTE they are all different for 1.20-1.40 and SX7-12
THFMI1v72.hex NOTE or other name for other M-link editions
SECOND
The update is initiated in the transmitter menu.
-----------PROBLEM-----------
If the update is inhibited by the wrong menu choice; zB Factory Reset, the touch screen will work but with the wrong graphics:
"SD Error" was communicated, but there is no SD error. My transmitter was in the "Stick Calibration" mode and therefore the touch was non-responsive.
-----------SOLUTION-----------
The only way to exit is to do the calibration by moving the sticks and watching the Corona 
After this was done, I came to the same screen as user istvan in post 6.
Since I have two identical SX9 transmitters I could very easily blind-navigate the menus despite the graphics being wrong and perform the update. Everything works!
For the solution I must thank the excellent Multiplex Customer Service. Only needed them a few times, but they always come through.
