Bootloading a Microcontroller using a Microcontroller

Hi Folks,

I wanna ask on how can I update the firmware of a microcontroller using another microcontroller with only UART connection.



Basically, I wanna load the data of the updated software in the PIC18F then use it to change the firmware of the EFM32 microcontroller.

Now, I have read in the internet that it is possible but can someone explain it in more easier terms since I'm just starting to learn microcontrollers.
If someone could, it will be very...

Bootloading a Microcontroller using a Microcontroller