Before anyone asks I have had the custom firmware installed since it came out. (Im on harleyg's one at the moment)
Are these defenitions near enough correct?
The file which is flashed to your PSP and is required for the recovery feature to be accessed when you boot your PSP
The file which is flashed to your PSP and is required for the new custom firmware features to be available (EG. 1.00 eboot launching, removing SCE start up etc.)