diff --git a/libraries/AP_HAL_ChibiOS/hwdef/CubeRedPrimary/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/CubeRedPrimary/hwdef.dat
index cbc174d9a55ac6..d6e7dfa8e38aad 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/CubeRedPrimary/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/CubeRedPrimary/hwdef.dat
@@ -98,7 +98,7 @@ PB14   SPI2_MISO    SPI2
 PB15   SPI2_MOSI    SPI2
 
 # SPI4
-PF5    ICM20649_CS   CS
+PF5    ICM_2_CS   CS
 PC2    BARO_1_CS   CS
 PE12    SPI4_SCK    SPI4
 PE5    SPI4_MISO    SPI4
@@ -111,12 +111,15 @@ SPIDEV ms5611_0         SPI1 DEVID2  BARO_0_CS          MODE3 20*MHZ 20*MHZ
 SPIDEV icm42688_1       SPI2 DEVID1  ICM42688_1_CS      MODE3  2*MHZ  8*MHZ
 SPIDEV rm3100           SPI2 DEVID2  RM3100_CS          MODE3  1*MHZ  1*MHZ
 
-SPIDEV icm20649         SPI4 DEVID1  ICM20649_CS        MODE3  4*MHZ  8*MHZ
+SPIDEV icm20649         SPI4 DEVID1  ICM_2_CS           MODE3  4*MHZ  8*MHZ
+# alternative to icm20649
+SPIDEV icm45686         SPI4 DEVID1  ICM_2_CS           MODE3  2*MHZ  8*MHZ
 SPIDEV ms5611_1         SPI4 DEVID2  BARO_1_CS          MODE3 20*MHZ 20*MHZ
 
 IMU Invensensev3 SPI:icm42688_1 ROTATION_YAW_90
 IMU Invensensev3 SPI:icm42688_0 ROTATION_PITCH_180_YAW_270
 IMU Invensensev2 SPI:icm20649 ROTATION_PITCH_180
+IMU Invensensev3 SPI:icm45686 ROTATION_YAW_180
 
 BARO MS56XX SPI:ms5611_0
 BARO MS56XX SPI:ms5611_1
@@ -124,6 +127,7 @@ BARO MS56XX SPI:ms5611_1
 COMPASS RM3100 SPI:rm3100 false ROTATION_YAW_270 
 
 CHECK_ICM20649        spi_check_register_inv2("icm20649", INV2REG_WHOAMI, INV2_WHOAMI_ICM20649)
+CHECK_ICM45686_2      spi_check_register("icm45686", INV3REG_456_WHOAMI, INV3_WHOAMI_ICM45686)
 
 CHECK_ICM42688_0      spi_check_register("icm42688_0", INV3REG_WHOAMI, INV3_WHOAMI_ICM42688)
 CHECK_ICM45686_0      spi_check_register("icm42688_0", INV3REG_456_WHOAMI, INV3_WHOAMI_ICM45686)
@@ -135,7 +139,7 @@ CHECK_MS5611_0        check_ms5611("ms5611_0")
 CHECK_MS5611_1        check_ms5611("ms5611_1")
 
 
-CHECK_IMU0_PRESENT      $CHECK_ICM20649
+CHECK_IMU0_PRESENT      $CHECK_ICM20649 || $CHECK_ICM45686_2
 CHECK_IMU1_PRESENT      $CHECK_ICM42688_0 || $CHECK_ICM45686_0
 CHECK_IMU2_PRESENT      $CHECK_ICM42688_1 || $CHECK_ICM45686_1
 CHECK_BARO0_PRESENT     $CHECK_MS5611_0