PCB pin-headers 5V-GND-RST-10-11-12-13 allows to program the ATtiny85 from an Arduino UNO, instead of Arduino Nano. Remove from PCB any pluged Arduino Nano if you are going to program the ATtiny85 ...
This project creates a complete standalone ISP programmer for Arduino Nano devices using another Arduino Nano as the programmer. It's designed to program the Optiboot bootloader onto ATmega328P ...