Hello,

I want to update firmware for my PIC24 chip, I know I will need some bootloader for that and I will work on that.
Still I have not finalized the interface that I may use for update. It might be USB or serial.

I was wondering if there is any application note from Microchip which can guide me to the steps that I have to take care and implement for the firmware upgrade?

Also how to setup the memory structure in such a way so my bootloader always be there even I do load new application code via PICKIT2.

 

This may prove to be useful:
http://www.picbasic.co.uk/forum/showthread.php?t=4498
as well as this App Note:
http://ww1.microchip.com/downloads/en/AppNotes/01094a.pdf (https://www.microchip.com/stellent/idcplgIdcService=SS_GET_PAGE&nodeId=1824&appnote=en530200)