diff --git a/sw/airborne/boards/lisa_m_common.h b/sw/airborne/boards/lisa_m_common.h
index 98f4081b48..133c8c1938 100644
--- a/sw/airborne/boards/lisa_m_common.h
+++ b/sw/airborne/boards/lisa_m_common.h
@@ -250,7 +250,7 @@
 #define USE_DUAL_PWM6 1
 #else
 #define USE_PWM5 1
-#ifndef USE_PWM6 // this allows to disable servo 6 on Lisa M
+#if (!defined USE_PWM6) && (PPM_CONFIG != 2) // PWM6 only activated by default if PPM_CONFIG is not 2
 #define USE_PWM6 1
 #endif
 #endif
diff --git a/sw/airborne/boards/lisa_mx_common.h b/sw/airborne/boards/lisa_mx_common.h
index d42a8514d6..822eba3a9c 100644
--- a/sw/airborne/boards/lisa_mx_common.h
+++ b/sw/airborne/boards/lisa_mx_common.h
@@ -420,7 +420,7 @@
 #define USE_PWM5 1
 #endif
 
-#ifndef USE_PWM6 // this allows to disable servo 6 on Lisa MXS
+#if (!defined USE_PWM6) && (PPM_CONFIG != 2) // PWM6 only activated by default if PPM_CONFIG is not 2
 #define USE_PWM6 1
 #endif