> What about verification?? No verification, at least no external acknowledgment. The bootloader should assure that the application is started only when all data is received and programmed correctly (internal verification). So when, after loading, the application starts, the loading must have been succesfull. You must have a way to check that the application is running, but that should not be too hard. You can not expect too much from a zero-IO-pin interface.... Wouter van Ooijen -- Van Ooijen Technische Informatica: http://www.voti.nl Jal compiler, Wisp programmer, WLoader bootloader, PICs kopen -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body