Not really related to the original topic but I'll offer an answer.
pratto:
if my conception of the process is about right, why not just continue to use the arduino bootloader ? my own question makes me wonder, is it so you can burn something other than the arduino bootloader ?just asking.
Not quite right.
A bootloader is a piece of software that can be put into the AVR chip.
If it is in there, it runs when the chip is powered up or reset.
The Arduino bootloader can be used to upload/burn
an application program (the sketch) into the flash using a serial port.
The bootloader also starts/runs your application code.
Every AVR based Arduino board comes with an AVR chip with an Arduino bootloader installed in it.
The IDE talks to the Arduino bootloader and communicates with the bootloader over a serial port
to burn a new application program.
If bootloader doesn't get a request to update the application code,
the bootloader will start the users application code (sketch).
An ISP programmer is a hardware device used to burn a bootlader in the AVR chip.
The USBasp programmer is one such ISP programmer.
An Arduino board can be loaded with software to allow it to be used as an ISP programmer.
The early Arduino bootloaders had a bug/code oversight in them in that if the application code
used the Watchdog timer and a watchdog reset occurs, the bootloader doesn't properly
initialize things after a watchdog reset and a watchdog reset occurs over and over again.
The way to fix this is to burn a new bootloader with updated code.
To burn a new bootloader in the AVR chip requires using an ISP programmer
and a cheap easy to use ISP programmer is the USBasp programmer than johnwasser referred
to.
Hope that clears it up.
--- bill