well that's an issue..that i was expecting, hence my question
one is supposed to be able to send any kind of data through serial interface
i guess i'll have to use Serial1 instead
You're not paying attention. The "!!!" sequence is ONLY an issue if you have a Mega bootloader AND it's an issue ONLY when the bootloader is receiving the data. The bootloader will NOT be running when your code is running AND you can't upload code on Serial1