OK thanks for your explanation.
I think my board has the Opti bootloader already.
Or is it a seperate sketch that is used to flash other chips?
Do I have to disconnect the USB interface?
Using your explanation I could flash a bootloader.
How can I flash a sketch?
Or do I have to use the AVR studio to generate a hex file?
I only have one USB interface right now, the one that is on the board.
Should I get another USB interface for the external chips?
I don't want to mess up the board more than neccessary and your advice maybe can save me from hours of experiments.
Or maybe I should get a seperate flash writer they are not expensive.