FREELOADER

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 https://protoncompiler.com/

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_C: 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.

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