boot loader confusion

[ucsam]

hey! guys
if i have a bootloader then does the bootloading needs to be done everytime i turn on and turn off the system?

I mean does the code stay there even if i turn off the power?

 

[bjuric]

Yes the program stays.

The bootloader is used on devices that support self-programming to reprogram the code, without the need for dedicated MCU programmer.
When you start the MCU, it takes incoming data and flashes itself, if no data is received in set amount of time (few seconds) than the existing program is executed as normal.