diff --git a/libraries/AP_HAL_ChibiOS/hwdef/CubeOrangePlus-SimOnHardWare/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/CubeOrangePlus-SimOnHardWare/hwdef.dat
index cf5b8ec4a4..9046dfbb06 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/CubeOrangePlus-SimOnHardWare/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/CubeOrangePlus-SimOnHardWare/hwdef.dat
@@ -3,6 +3,9 @@
 include ../CubeOrangePlus/hwdef.dat
 include ../include/SimOnHW.inc
 
+undef INS_AUX_INSTANCES
+define INS_AUX_INSTANCES 0
+
 # short board name override (23 chars)
 define CHIBIOS_SHORT_BOARD_NAME "CubeOrange+SimOnHW"