E1.37-4 File Transfer Control

[dj41354]

That's a lot of good information.. thank you. My target is an 8bit PIC18F46K22 and doesn't have the ability to hold a complete image for verification before programming. My current bootloader sends & programs in small blocks (64bytes) as the blocks come in. They're never sent out of order, and sending is paced such that the programming of the 64byte block always finishes before the next block is received.. that means there's no handshake necessary and the sending is simply streamed until complete. It's a Intel HEX file that gets sent, so there are embedded checksums that allow the bootloader to check the data, and flag a bad block to stop the programming process.. but if that happens in the middle, it is possible to brick the target.. and while it does occasionally happen, it's really rare. It sounds like the RDM based bootloading might be more susceptible to issues than what I'm currently using?.. I'll continue to look into this.. Thanks again. DougJ