FREELOADER
Jon Walker
Embedded Files
FREELOADER
Free PIC18 bootloader and uploader — by Jon Walker
FREELOADER gets new firmware into a PIC18 over a plain serial link, with no programmer on the bench. You flash the tiny mwboot bootloader HEX into the chip once with a PICkit. After that, you update the application from your PC with the FREELOADER Windows app or the mwload command-line tool.
It was written by a working engineer for real hardware. It's small, it's fast, and it's proven on the bench.
Bootloaders can be used with Positron Basic Compiler by Les Johnson POSITRON COMPILER
In addition, there is an accompanying friendly forum here: POSITRON FORUM
What you get
MWBOOT: a 776-byte bootloader that sits at the top of flash and stays out of your application's way
FREELOADER_GUI: a Windows 10/11 GUI to upload, read back, verify, erase and identify the part
FREELOADER_CMD: a command-line uploader. Win 95 - Win11
44 PIC18 parts across the Q43, K42, K40, K83, K22 and K20 families
Serial at 115200 baud, CRC-checked frames, and a protected reset vector, so a failed upload never bricks the chip
Auto-reset via RTS or DTR, so no button presses are needed
Full manuals
Free, and it stays free
FREELOADER is free for anyone, anywhere, including for commercial products. You can ship the bootloader inside your own products at no cost. It may not be sold, modified for redistribution, or rebadged. See the licence for the full terms.
WHAT! No board to play with?
You can buy a pre-built development platform that will work with all of the bootloaders from https://easy-driver.co.uk/amicus/ (John Lawton on the Forum)
LICENSE
FREELOADER, mwboot and mwload
Copyright (c) 2026 Jon Walker. All rights reserved.
Free licence. This licence applies worldwide. You may, free of charge:
1. Use these files, and the programs and bootloaders built from them, for any purpose, including commercial products.
2. Ship the compiled bootloader inside your own products' firmware, with no fee and no notice required in the product.
3. Change the files for your own use, including the Device line, pins, clock and baud settings needed for your board.
4. Pass on exact, unmodified copies of the complete package, including this licence.
5. Include FREELOADER.exe, unmodified, in your own installer or application, provided that installer or application is given away free of charge.
You may not, without the author's written permission:
6. Distribute modified versions of the source, programs or manuals.
7. Remove or alter the copyright notices, the author's name, the "FREELOADER by Jon Walker" title, or this licence.
8. Sell these files or FREELOADER.exe, or charge for them in any way, on their own or as part of anything that is sold.
9. Include the Python source files (mwload.py, mwload_gui.py and the other .py files) in your own installer, application or tool.
Contact the author first. (FREELOADER.exe itself is fine - see 5.)
Anyone who breaks these terms loses this licence automatically.
No warranty. These files are provided "as is". The author accepts no liability for any loss or damage arising from their use, as far as the law allows. Governed by the law of England and Wales.
Third-party software inside FREELOADER.exe: pyserial - Copyright (c) 2001-2020 Chris Liechti; BSD 3-Clause licence. Python and Tcl/Tk - under their own licences (PSF, Tcl/Tk licence).
Questions or bug reports: mwave.dude@gmail.com
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