Trouble running CubePurple Rover SimOnHardware

Hi,
I followed the instructions for running sim on hardware (rover) for my board, a CubePurple. I essentially copied the CubeOrange hwdef.dat and defaults.parm files, and then started whittling them down after it didn’t work right away. The firmware builds and loads to the board, and it boots. I am able to connect via Mission Planner. However, I get repeated “Config Error: fix problem and then reboot” messages. Any ideas?

Here is the Mission Planner output log:
2/16/2024 3:18:23 PM : Config Error: fix problem then reboot
2/16/2024 3:18:18 PM : Config Error: fix problem then reboot
2/16/2024 3:18:13 PM : Config Error: fix problem then reboot
2/16/2024 3:18:08 PM : Config Error: fix problem then reboot
2/16/2024 3:18:07 PM : RCOut: Initialising
2/16/2024 3:18:07 PM : IOMCU: 420 1001 411FC231
2/16/2024 3:18:07 PM : CubePurpleSimOnHardWare 00430044 43565010 2030385
2/16/2024 3:18:07 PM : ChibiOS: cc37d7f2
2/16/2024 3:18:07 PM : ArduRover V4.6.0-dev (4b5553ac)
2/16/2024 3:18:07 PM : RCOut: Initialising
2/16/2024 3:18:07 PM : IOMCU: 420 1001 411FC231
2/16/2024 3:18:07 PM : CubePurpleSimOnHardWare 00430044 43565010 2030385
2/16/2024 3:18:07 PM : ChibiOS: cc37d7f2
2/16/2024 3:18:07 PM : ArduRover V4.6.0-dev (4b5553ac)
2/16/2024 3:18:07 PM : RCOut: Initialising
2/16/2024 3:18:07 PM : IOMCU: 420 1001 411FC231
2/16/2024 3:18:07 PM : CubePurpleSimOnHardWare 00430044 43565010 2030385
2/16/2024 3:18:07 PM : ChibiOS: cc37d7f2
2/16/2024 3:18:07 PM : ArduRover V4.6.0-dev (4b5553ac)

My hwdef.dat:

# Firmware suitable for flashing into a CubePurple to experience Simulation-on-Hardware

include ../CubePurple/hwdef.dat
include ../include/SimOnHW.inc

# short board name override (23 chars)
define CHIBIOS_SHORT_BOARD_NAME "CubePurpleSimOnHardWare"

# bootloader embedding / bootloader flashing not available
define AP_BOOTLOADER_FLASHING_ENABLED 0

AUTOBUILD_TARGETS Rover

and defaults.parm:

AHRS_EKF_TYPE 10
GPS_TYPE 100
SIM_MAG1_DEVID 97539
SIM_BARO_RND    0

SIM_RATE_HZ 400

EK2_PRIMARY 1
EK3_PRIMARY 1

I’m building and loading in WSL2 with the provided sitl-on-hw.py script:
./Tools/scripts/sitl-on-hardware/sitl-on-hw.py --board CubePurple-SimOnHardware --vehicle rover --simclass SimRover --upload