To burn the bootloader, follow these steps:
Upload the ArduinoISP sketch onto your Arduino board(ProMini). (You'll need to select the board and serial port from the Tools menu that correspond to your board.)
Wire up the Arduino board and microcontroller as shown in the diagram to the right.
Select "Arduino Duemilanove or Nano w/ ATmega328" from the Tools > Board menu.
Select "Arduino as ISP" from Tools > Programmer
Run Tools > Burn Bootloader
Useful resource :
1. T³: Programming an ATtiny84A from Arduino
2. From Arduino to a Microcontroller on a Breadboard
3. From Arduino Uno to ATmega328 – Shrinking your Arduino Projects
