One should note, though, that xpatch.cpp only contains the code for the patch itself (including all the patch cords). It still relies on a number of things being in the flash ROM in the Axoloti, such as:
- Chibios (the multi tasking OS at the heart of the Axoloti)
- The CMSIS DSP library made specially for the STM32 processor series with its ARM core augmented with DSP functionality
- Other common things such as SD card and MIDI managment
Especially CMSIS might be a bit of a stumper, as several Axoloti objects make direct calls to the library (have a look at the code of some of the filter objects for instance). The equivalent functions can certainly be implemented on any other platform, but at a certain amount of development cost.
In the end, the best bet is probably getting the Axoloti running on another more powerful STM32 platform, which would require minimal changes to the firmware. I haven't kept up to date on what's available, but given that the Axoloti is several years old by now, it's likely that there is a more powerful STM32 platform available that it could be ported to.
A couple of years ago I ported the Axoloti to the Audiothingies P6, so that I could run Axoloti patches on the P6 hardware, inluding access to the display and encoders. It was mostly a question of differing GPIO assignments and DAC, and a couple of more complex issues like the clock crystal frequencies being different. But the STM32F405 used in the P6 is quite similar to the STM32F427 used in the Axoloti so the amount of changes needed were rather limited.