Aha, thanks for the fast answers, in the Gen/ article I read: "A bootloader compiled for 16 MHz won't work on an ATmega running at 20 MHz and vice versa. Again, make sure to choose the right variant."
@majic79: "so long as you match the clock inputs correctly (usually)." so then i just use the 16mhz bootloader anyway?
@Traumflug: "but fuses for 16 MHz and 20 MHz are the same" is there another definition in the upload process for the differentiation between 16 and 20mhz? because if the fuses are the same then the differentiation shouldnt matter?
@majic79: "so long as you match the clock inputs correctly (usually)." so then i just use the 16mhz bootloader anyway?
@Traumflug: "but fuses for 16 MHz and 20 MHz are the same" is there another definition in the upload process for the differentiation between 16 and 20mhz? because if the fuses are the same then the differentiation shouldnt matter?