diff --git a/libraries/AP_HAL_ChibiOS/hwdef/fmuv5/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/fmuv5/hwdef.dat
index b1735998e9..1816f441e0 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/fmuv5/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/fmuv5/hwdef.dat
@@ -76,6 +76,16 @@ PF4  BMI055_G_CS CS
 PG10 BMI055_A_CS CS
 PF5  FRAM_CS CS SPEED_VERYLOW
 
+# unusued CS pins
+PF11 SPARE_CS CS
+PH5  AUXMEM_CS CS
+PI4  EXTERNAL1_CS1 CS
+PI10 EXTERNAL1_CS2 CS
+PI11 EXTERNAL1_CS3 CS
+PI6  EXTERNAL2_CS1 CS
+PI7  EXTERNAL2_CS2 CS
+PI8  EXTERNAL2_CS3 CS
+
 # I2C buses
 
 PB8 I2C1_SCL I2C1