FotS

The source code for the Picomites is available here.
The compiled binaries and documentation are readily available here.
If you want to compile your own binary the key information required to compile the code is listed in the readme of the source. In general the developers cannot/don't give support in the setup of the development environment as there are many moving parts and remote support can be very time consuming and difficult.

This contains files to build MMbasic 6.01.00b7 to run on both RP2040 and RP2350
Compile with GCC 13.3.1 arm-none-eabi
Build with sdk V2.2.0 but replace gpio.c, gpio.h with the ones included here
Change CMakeLists.txt line 4 to determine which variant to build

RP2040
set(COMPILE PICO)
set(COMPILE VGA)
set(COMPILE PICOUSB)
set(COMPILE VGAUSB)
set(COMPILE WEB)

RP2350
set(COMPILE PICORP2350)
set(COMPILE VGARP2350)
set(COMPILE PICOUSBRP2350)
set(COMPILE VGAUSBRP2350)
set(COMPILE HDMI)
set(COMPILE HDMIUSB)
set(COMPILE WEBRP2350)

Any of the RP2350 variants or the RP2040 variants can be built by simply changing 
the set(COMPILE aaaa)
However, to swap between a rp2040 build and a rp2350 build (or visa versa) needs
a different build directory. 
The process for doing this is as follows:
Close VSCode
Rename the current build directory - e.g. build -> buildrp2040
Rename the inactive build directory - e.g. buildrp2350 -> build
edit CMakeLists.txt to choose a setting for the other chip and save it -
e.g. set(COMPILE PICO) -> set(COMPILE PICORP2350)
Restart VSCode

Compile with GCC 13.3.1 arm-none-eabi 
This contains files to build MMbasic V6.00.03 to run on both RP2040 and RP2350
Build with sdk V2.1.1 but replace gpio.c, gpio.h, float_sci_m33_vfp.S, and flash.c
with the ones included here e.g.
xcopy .\PicoMite\gpio.c "~\pico-sdk\src\rp2_common\hardware_gpio" \\
xcopy .\PicoMite\gpio.c "~\pico-sdk\src\host\hardware_gpio"\\
                         ~/pico/pico-sdk/src/rp2_common/pico_float/float_sci_m33_vfp.S\\

Change CMakeLists.txt line 4 to determine which variant to build\\

This post by TBS by member @karlelch contains an example and a detailed instruction for the setup of a Windows 11 environment which may be helpful.

TBS thread with example

How to by @karlelch on TBS

Another thread about loading the tool chain

pico sdk

backslash error affects non windows compile The backslash “\” rather than forward slash “/” keeps the compiler from finding the file on non-Windows platforms (I'm on a Mac) This is an issue in 3 files: Functions.c, MATHS.c, MM_Misc.c.

Linux Compile

Saving the entire pico "image" - .uf2