It seems in the MPLAB help that the debugger reserves 100 bytes in top of memory for debug purposes. The hex file I am trying to program is a bootloader and is destined for those top 100 bytes. Can anyone verify that MPLAB always reserves this 100 bytes or only if you have "Debug mode" enabled in program options ? regards David Huisman -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu