Bootloader utilizes to program microcontrollers by providing a medium of communication between them. Hence small bootloader uses to make controller programmable very often as like Arduino series board. Microcontrollers like 8051, PIC without bootloader requires the external programmer to burn the program inside the memory of the microcontroller. In addition to it requires preciously control output states of various pin mode which should be in sequence according to the datasheet of the manufacturer. Here this PPT has portrayed as an example of idle configurations that requires to run the bootloader and what happens if the bootloader is installed inside the memory of the controller.