The 2.2 version of the firmware_xxx bin file contained the 2.2 firmware as well as the boot loader and the original Archos firmware.
This has now changed, and the firmware_xxx file only contains the boot loader and the original Archos firmware. After the initial flashing, the only thing that has happened is that the flash is *prepared* for flashing Rockbox. It still starts the original firmware, since Rockbox is not yet in flash.
To put Rockbox in the flash as well, you do the same as you do to update the flash, i.e play the /.rockbox/rockbox.ucl file.