Hi sir..regarding the bootloader in Open Source Framework for USB Generic HID devices based on the PIC18F and Windows, is it use to program the PIC without using the PICKit when we want to modify the firmware? if yes, how to do that? is it need a host software to do it?

Yes you can use it to program the PIC without a programmer, and the host software is available within the microchip USB stack examples (which you can download from Microchip). The only snag is that you need a programmer to put the bootloader on the chip in the first place.

The general idea is that you program the chips and send them out in to the field, then, when it's time to upgrade the firmware, the installation program can use boot loading to do it without any equipment required.

/Simon

Thanks for reply Simon..
The firmware was writen in Microchip C18 compiler, does it support HI-TECH compiler also? if i want to add the bootloader function to my project, am I just need add in the rm18f4550 - HID Bootload.lkr file to my firmware?

The latest version of the HID firmware is only for the Microchip C18 compiler (previous versions were for HiTech but I discovered that the (insane) licencing on the application stack from Microchip meant that I could only use C18).

I have to admit I have not played with boot loaders via USB on the PICs (always had a programmer handy so never felt the need). There should be a wealth of information on the subject over on the microchip forums though.