@EdChamberlain It's working but I've taken small breaks to build some other hardware.
The core of the SB2040 toolboard is working great. I am looking into I2C in order to add an LIS3DH accelerometer, but the I2C libs aren't wired up into the RP2040 yet.
I had a few issues with my environment and now can compile both the 3.5 code for RP2040 and Jay's branch.
Does anyone know when I2C might be ready to test on the RP2040? I'm digging around but I'm getting a little lost.