Owlware Legacy firmware

jagspaul · November 29, 2025, 6:13am

I have STM32F407 board. I want to load Olwware runtime and patch on it to build a guitar processor.
I have gone through Owl legacy schematic and I managed to modify my hardware as per the schematic.

pingdynasty (Martin Klang) · GitHub
OwlWare legacy I have gone through this repo.

Still I have some understanding and question regarding OwlWare legacy.

Hope OwlWare legacy is working and bug free.
I have managed to build OwlWare legacy with 19 patch only out of so many patches. for other patches I get many errors. So I decided to start with this 19 patches. This patches are build along with Owl runtime.
I have found 4 memory location each 128 KB for 4 dynamic patch. My question is is it true that this OwlWare legacy support dynamic patch loading also? If so please explain how I build dynamic patch separately with owl runtime build? How this dynamic patch call owl runtime functions ? How patch building linker script knows pointer of the owl runtime functions?

I really very much confuse about this technique how owl works and manage this.

Thanks and regards
jags

antisvin · November 30, 2025, 1:50pm

OwlWare is unsupported for many years. It doesn’t have any obvious bugs, but also is way less advanced than OpenWare. And OpenWare runs on the same OWL1 hardware, so you should be able to use it too.
Yes, you should be able to replace 4 patch as you’ve understood already. On OpenWare you don’t have any prebuilt patches, you can write your own in every patch slot
The short story is that there’s a shared datastructure that is found under address known to firmware from patch executable header. It’s used to exchanged various pointers to data and functions between patch and firmware.

Here are some relevant places on patch side:

github.com

RebelTechnology/OwlProgram/blob/develop/Source/ProgramVector.h

#ifndef __PROGRAM_VECTOR_H
#define __PROGRAM_VECTOR_H

#include <stdint.h>

#ifdef __cplusplus
 extern "C" {
#endif

#define OWL_PEDAL_HARDWARE    0x11
#define OWL_MODULAR_HARDWARE  0x12
#define OWL_RACK_HARDWARE     0x13
#define PRISM_HARDWARE        0x14
#define PLAYER_HARDWARE       0x15

#define PROGRAM_VECTOR_CHECKSUM_V11 0x40
#define PROGRAM_VECTOR_CHECKSUM_V12 0x50
#define PROGRAM_VECTOR_CHECKSUM_V13 0x51

#define CHECKSUM_ERROR_STATUS        -10

This file has been truncated. show original

github.com

RebelTechnology/OwlProgram/blob/develop/Source/owl1.ld#L119-L129

    
      
          .pv (NOLOAD) :
          {
            . = ALIGN(8);
            _programvector = ABSOLUTE(.);
              *(.pv)
            . = ALIGN(8);
            PROVIDE ( _eprogram = . );
            PROVIDE ( _stack = . );
          } >PATCHRAM
          _eram = ORIGIN(PATCHRAM) + 80k;    /* Limit to 80k for OwlWare compatiblity */
          _estack = ORIGIN(PATCHRAM) + 80k;

github.com

RebelTechnology/OwlProgram/blob/develop/Source/startup.s#L75-L82

    
      
          g_pfnVectors:

            .word 0XDADAC0DE       /* magic */

            .word _startprog 	 /* link base address */

            .word _endprog         /* end of program */

            .word Reset_Handler    /* code entry point */

            .word _stack           /* stack start */

            .word _estack          /* stack end */

            .word _programvector

jagspaul · November 30, 2025, 8:19pm

antisvin:

g_pfnVectors:

            .word 0XDADAC0DE       /* magic */

            .word _startprog 	 /* link base address */

            .word _endprog         /* end of program */

            .word Reset_Handler    /* code entry point */

            .word _stack           /* stack start */

            .word _estack          /* stack end */

            .word _programvector

Thanks for you kind reply and explanation.

You are telling OwlWare less advanced than OpenWare. And OpenWare runs on the same OWL1 hardware. But sill I like OwlWare as because it cab be made as runtime + many factory patch(maybe 40) . However OpenWare only support dynamic patch in multiple slot, but still I have question openwire running on OWL1, how much maximum slot available which can be permanently stored in flash so that every time on power on patch loading is not mandatory.

Thanks
jags

antisvin · December 1, 2025, 2:53pm

It uses 40 patch slots by default too. It can be changed at compile time as long as you have sufficient space in patch storage. Also, an actual OWL2/3 board has an external 8MB NOR flash chip that is used as storage instead of internal flash.

jagspaul · December 1, 2025, 4:19pm

Very nice.
Now I need OWL hardware Board. I have search the git repo and only find OWL1 schematic. OWL1 gerber not available.
Also OWL2/3 neither found schematic nor found gerber.

In this connection you are requested to provide me OWL1 gerber and OWL2/3 schematic and gerber too.

Also I need to purchase complete PCB of OWL1/2/3, You are again requested to guide me how to purchase the same with best price.

Please note that I am from India and the product will be shipped to India only.

Thanks
Jags

antisvin · December 1, 2025, 4:29pm

Sorry, I’m not an official support for this product, so I don’t fulfill requests. You should be able to buy OWL3 board in Befaco store, but it’s out of stock at the moment. Older boards are not produced. And I don’t think they’ve released schematics or gerber files for newer boards.