Solved !
What did i do:
Downloaded the SPD Tool and the coolpix pac file and installed as
@Momchil suggested.
Importantst step was to use a OTG Cable and a USB A to A connector and connect the ST10+ to the PC.
Connect the OTG between pc and ST10+ but without battery attached.
Insert a fresh formatted SD Card into the Slot with update.zip from a usable yuneec update on it in root directory.
Started SPD Tool and select the .pac file and klick on the play button in spd tool.
After all that will be made connect the Battery into ST10+ don‘t do it before !
As next i got a Chinese Startup screen.
While i tapped few times on the Display ( i believe 10 times if i remember correct) a new Screen appears.
In that screen i found an install button, so i klicked it and i got response what file i would like to install.
I selected the update.zip in the root of sdcard and the reboot after done and hit the „ do it“
As next i see few things like an install would be happen.
Here is the Screenshot about.
Than the ST10+ suddenly reboots and i hear the yuneec sound but nothing more, the screen appears to be black further.
I removed the Battery and give her a New Start.
First the Chinese Startscreen, followed by yuneec Startsound with the Yuneec Logo.
After that the screen keeps a rotary symbol for about 3 min than it do itself a restart and all seems fine, except the first bootscreen, that was further the chinese one.
however, maybe i can change it later.
Maybe this will help few guys to bring their ST10+ back to life.
@WTFDproject maybe that helps you also.
Please feedback, thanks.
Regards Schteffl