Kiwi is Dooba's bootloader for AVR microcontrollers.
When power is applied to the microcontroller, it starts executing Kiwi.
Kiwi will then wait for 4 seconds. If a dflash instruction is received within that time, the wait timer is cancelled and the flashing process starts.
If nothing happens within those 4 seconds, Kiwi will start executing whatever application is stored in flash memory.
Another way to trigger Kiwi is to pulse the RESET line (active low) of the microcontroller.