If I replace the bootloader with my sketch, will my remote control start working instantely (like fractions of a second)?
If yes, do I need to change something in my sketch?
Like what? Do you need a delay at startup?
A clarification: Will I need to add some header files etc to my sketch
or just upload (via programmer)
and the sketch will run automatically, ie start with setup() and then loop() ?
I don't want nor need a delay, just want it to start immediately
...However if you want zero delay and you have a hardware programmer, one can burn the sketch's hex file into a blank chip that has no bootloader installed and the sketch will start without any delay at all. There is no software changes needed to the sketch to use this option. However the fuse settings used for the chip will be different if there is no bootloader then if there are.If you have one of the hardware programmers supported by the arduino IDE, then there is a way to burn sketches onto a chip without it having a bootloader by modifying the boards.txt file in the Arduino core files, but I can't seem to find the link in the Arduino playground at this time.