Arduino Nano with ATmega328P is available in two variants: "ATmega328P" and the older "ATmega328P (Old Bootloader)". The newer variant uses an optimized bootloader which has double upload transfer ...

Have you been tinkering around with these cheap and accesible Arduino-boards for a while, and felt like. Hmm whats the next step up the ladder? A first step could be to set up a productive environment ...