diff --git a/ROMFS/px4fmu_common/init.d/rc.axialracing_ax10_apps b/ROMFS/px4fmu_common/init.d/rc.axialracing_ax10_apps
index 0466ef9b83..1a46605357 100644
--- a/ROMFS/px4fmu_common/init.d/rc.axialracing_ax10_apps
+++ b/ROMFS/px4fmu_common/init.d/rc.axialracing_ax10_apps
@@ -1,10 +1,15 @@
 #!nsh
 #
 # Standard apps for rovers:
-# att & pos estimator, rover steering control
+# Attitude/Position estimator and rover steering control.
+#
+# NOTE: Script variables are declared/initialized/unset in the rcS script.
 #
 
+#
+# Start the Attitude estimator.
+#
 ekf2 start
 
 # disabled the start of steering control app due to use of offboard mode only
-# rover_steering_control start
+# rover_steering_control start.
diff --git a/ROMFS/px4fmu_common/init.d/rc.axialracing_ax10_defaults b/ROMFS/px4fmu_common/init.d/rc.axialracing_ax10_defaults
index 7caac82b54..fa0563e127 100644
--- a/ROMFS/px4fmu_common/init.d/rc.axialracing_ax10_defaults
+++ b/ROMFS/px4fmu_common/init.d/rc.axialracing_ax10_defaults
@@ -1,26 +1,36 @@
 #!nsh
+#
+# Standard defaults for rovers.
+#
+# NOTE: Script variables are declared/initialized/unset in the rcS script.
+#
 
 set VEHICLE_TYPE ugv
 
+#
 # This section can be enabled once tuning parameters for this particular
-# rover model are known. It allows to configure default gains via the GUI
+# rover model are known. It allows to configure default gains via the GUI.
+#
 if [ $AUTOCNF == yes ]
 then
-	# PWM default value for "disarmed" mode
-	# this centers the steering and throttle, which means no motion
-	# for a rover
+	# PWM default value for "disarmed" mode.
+	# This centers the steering and throttle, which means
+	# no motion for a rover.
 	param set PWM_DISARMED 1500
 
-	# PWM range
+	# PWM range.
 	param set PWM_MIN 1200
 	param set PWM_MAX 1800
 fi
 
+#
 # PWM Hz - 50 Hz is the normal rate in RC cars, higher rates
 # may damage analog servos.
+#
 set PWM_RATE 50
 
-# Enable servo output on pins 3 and 4 (steering and thrust)
-# but also include 1+2 as they form together one output group
-# and need to be set together.
+#
+# Enable servo output on pins 3 and 4 (steering and thrust) but also
+# include 1+2 as they form one output group and need to be set together.
+#
 set PWM_OUT 1234
diff --git a/ROMFS/px4fmu_common/init.d/rc.fw_defaults b/ROMFS/px4fmu_common/init.d/rc.fw_defaults
index 87d7fe4029..4d65de2ac1 100644
--- a/ROMFS/px4fmu_common/init.d/rc.fw_defaults
+++ b/ROMFS/px4fmu_common/init.d/rc.fw_defaults
@@ -28,8 +28,10 @@ then
 	param set RTL_DESCEND_ALT 100
 	param set RTL_LAND_DELAY -1
 
-	# FW uses L1 distance for acceptance radius,
-	#  set a smaller NAV_ACC_RAD for vertical acceptance distance.
+	#
+	# FW uses L1 distance for acceptance radius.
+	# Set a smaller NAV_ACC_RAD for vertical acceptance distance.
+	#
 	param set NAV_ACC_RAD 10
 
 	param set MIS_LTRMIN_ALT 25
@@ -37,11 +39,16 @@ then
 
 	param set PWM_RATE 50
 
+	#
 	# FW takeoff acceleration can easily exceed ublox GPS 2G default.
+	#
 	param set GPS_UBX_DYNMODEL 8
 fi
 
+#
 # This is the gimbal pass mixer.
+#
 set MIXER_AUX pass
+
 set PWM_AUX_RATE 50
 set PWM_AUX_OUT 1234
diff --git a/ROMFS/px4fmu_common/init.d/rc.interface b/ROMFS/px4fmu_common/init.d/rc.interface
index f581d9707a..9c6d46a41d 100644
--- a/ROMFS/px4fmu_common/init.d/rc.interface
+++ b/ROMFS/px4fmu_common/init.d/rc.interface
@@ -1,6 +1,6 @@
 #!nsh
 #
-# Script to configure control interface
+# Script to configure control interfaces.
 #
 #
 # NOTE: environment variable references:
diff --git a/ROMFS/px4fmu_common/init.d/rc.mc_apps b/ROMFS/px4fmu_common/init.d/rc.mc_apps
index 7650e117ee..b48fa3f4cb 100644
--- a/ROMFS/px4fmu_common/init.d/rc.mc_apps
+++ b/ROMFS/px4fmu_common/init.d/rc.mc_apps
@@ -8,7 +8,10 @@
 ###############################################################################
 #                       Begin Estimator Group Selection                       #
 ###############################################################################
+
+#
 # INAV (deprecated).
+#
 if param compare SYS_MC_EST_GROUP 0
 then
 	echo "ERROR [init] Estimator INAV deprecated. Using EKF2"
@@ -16,11 +19,15 @@ then
 	param save
 fi
 
+#
 # LPE
+#
 if param compare SYS_MC_EST_GROUP 1
 then
-	# Try to start LPE. If it fails, start EKF2 as a default
+	#
+	# Try to start LPE. If it fails, start EKF2 as a default.
 	# Unfortunately we do not build it on px4fmu-v2 due to a limited flash.
+	#
 	if attitude_estimator_q start
 	then
 		local_position_estimator start
@@ -31,7 +38,9 @@ then
 	fi
 fi
 
+#
 # EKF2
+#
 if param compare SYS_MC_EST_GROUP 2
 then
 	ekf2 start
diff --git a/ROMFS/px4fmu_common/init.d/rc.mc_defaults b/ROMFS/px4fmu_common/init.d/rc.mc_defaults
index bf33c1d2e1..aca06e9967 100644
--- a/ROMFS/px4fmu_common/init.d/rc.mc_defaults
+++ b/ROMFS/px4fmu_common/init.d/rc.mc_defaults
@@ -20,7 +20,10 @@ then
 	param set PWM_RATE 400
 fi
 
+#
 # This is the gimbal pass mixer.
+#
 set MIXER_AUX pass
+
 set PWM_AUX_RATE 50
 set PWM_AUX_OUT 1234
diff --git a/ROMFS/px4fmu_common/init.d/rc.sensors b/ROMFS/px4fmu_common/init.d/rc.sensors
index b8dadcfbda..b893f0aa04 100644
--- a/ROMFS/px4fmu_common/init.d/rc.sensors
+++ b/ROMFS/px4fmu_common/init.d/rc.sensors
@@ -2,6 +2,8 @@
 #
 # Standard startup script for sensor drivers.
 #
+# NOTE: Script variables are declared/initialized/unset in the rcS script.
+#
 
 ###############################################################################
 #               Begin Setup for board specific configurations.                #
diff --git a/ROMFS/px4fmu_common/init.d/rc.ugv_defaults b/ROMFS/px4fmu_common/init.d/rc.ugv_defaults
index 53a6b4603f..0e8d7ddbf0 100644
--- a/ROMFS/px4fmu_common/init.d/rc.ugv_defaults
+++ b/ROMFS/px4fmu_common/init.d/rc.ugv_defaults
@@ -10,7 +10,7 @@ set VEHICLE_TYPE ugv
 if [ $AUTOCNF == yes ]
 then
 #
-# Default parameters for UGVs
+# Default parameters for UGVs.
 #
 	param set MIS_LTRMIN_ALT 0.01
 	param set MIS_TAKEOFF_ALT 0.01
@@ -18,20 +18,26 @@ then
 	param set NAV_DLL_ACT 0
 	param set NAV_ACC_RAD 2.0
 
-	# temporary
+	# Temporary.
 	param set NAV_FW_ALT_RAD 1000
 fi
 
+#
 # Enable servo output on pins 3 and 4 (steering and thrust)
 # but also include 1+2 as they form together one output group
 # and need to be set together.
+#
 set PWM_OUT 1234
 
+#
 # PWM Hz - 50 Hz is the normal rate in RC cars, higher rates
 # may damage analog servos.
+#
 set PWM_RATE 50
 
-# This is the gimbal pass mixer
+#
+# This is the gimbal pass mixer.
+#
 set MIXER_AUX pass
 set PWM_AUX_RATE 50
 set PWM_AUX_OUT 1234
diff --git a/ROMFS/px4fmu_common/init.d/rc.vehicle_setup b/ROMFS/px4fmu_common/init.d/rc.vehicle_setup
index d4d0a9f196..54f3a8da1b 100644
--- a/ROMFS/px4fmu_common/init.d/rc.vehicle_setup
+++ b/ROMFS/px4fmu_common/init.d/rc.vehicle_setup
@@ -6,19 +6,19 @@
 #
 
 #
-# Fixed wing setup
+# Fixed wing setup.
 #
 if [ $VEHICLE_TYPE == fw ]
 then
 	if [ $MIXER == none ]
 	then
-		# Set default mixer for fixed wing if not defined
+		# Set default mixer for fixed wing if not defined.
 		set MIXER AERT
 	fi
 
 	if [ $MAV_TYPE == none ]
 	then
-		# Use MAV_TYPE = 1 (fixed wing) if not defined
+		# Use MAV_TYPE = 1 (fixed wing) if not defined.
 		set MAV_TYPE 1
 	fi
 
@@ -32,7 +32,7 @@ then
 fi
 
 #
-# Multicopters setup
+# Multicopter setup.
 #
 if [ $VEHICLE_TYPE == mc ]
 then
@@ -82,7 +82,7 @@ then
 		fi
 	fi
 
-	# Still no MAV_TYPE found
+	# Still no MAV_TYPE found.
 	if [ $MAV_TYPE == none ]
 	then
 		param set MAV_TYPE 2
@@ -90,15 +90,15 @@ then
 		param set MAV_TYPE ${MAV_TYPE}
 	fi
 
-	# Load mixer and configure outputs
+	# Load mixer and configure outputs.
 	sh /etc/init.d/rc.interface
 
-	# Start standard multicopter apps
+	# Start standard multicopter apps.
 	sh /etc/init.d/rc.mc_apps
 fi
 
 #
-# VTOL setup
+# VTOL setup.
 #
 if [ $VEHICLE_TYPE == vtol ]
 then
@@ -109,7 +109,7 @@ then
 
 	if [ $MAV_TYPE == none ]
 	then
-		# Use mixer to detect vehicle type
+		# Use mixer to detect vehicle type.
 		if [ $MIXER == caipirinha_vtol ]
 		then
 			set MAV_TYPE 19
@@ -124,7 +124,7 @@ then
 		fi
 	fi
 
-	# Still no MAV_TYPE found
+	# Still no MAV_TYPE found.
 	if [ $MAV_TYPE == none ]
 	then
 		echo "Unknown MAV_TYPE"
@@ -133,10 +133,10 @@ then
 		param set MAV_TYPE ${MAV_TYPE}
 	fi
 
-	# Load mixer and configure outputs
+	# Load mixer and configure outputs.
 	sh /etc/init.d/rc.interface
 
-	# Start standard vtol apps
+	# Start standard vtol apps.
 	sh /etc/init.d/rc.vtol_apps
 fi
 
@@ -147,22 +147,22 @@ if [ $VEHICLE_TYPE == ugv ]
 then
 	if [ $MIXER == none ]
 	then
-		# Set default mixer for UGV if not defined
+		# Set default mixer for UGV if not defined.
 		set MIXER ugv_generic
 	fi
 
 	if [ $MAV_TYPE == none ]
 	then
-		# Use MAV_TYPE = 10 (UGV) if not defined
+		# Use MAV_TYPE = 10 (UGV) if not defined.
 		set MAV_TYPE 10
 	fi
 
 	param set MAV_TYPE ${MAV_TYPE}
 
-	# Load mixer and configure outputs
+	# Load mixer and configure outputs.
 	sh /etc/init.d/rc.interface
 
-	# Start standard UGV apps
+	# Start standard UGV apps.
 	sh /etc/init.d/rc.ugv_apps
 fi
 
diff --git a/ROMFS/px4fmu_common/init.d/rcS b/ROMFS/px4fmu_common/init.d/rcS
index 87d1ced50f..59d1410c74 100644
--- a/ROMFS/px4fmu_common/init.d/rcS
+++ b/ROMFS/px4fmu_common/init.d/rcS
@@ -46,7 +46,7 @@ set +e
 #
 
 #
-# Set default paramter values
+# Set default paramter values.
 #
 set AUX_MODE                    pwm
 set DATAMAN_OPT                 ""
@@ -157,12 +157,12 @@ else
 	uorb start
 
 	#
-	# Start tone driver.
+	# Start the tone_alarm driver.
 	#
 	tone_alarm start
 
 	#
-	# Play startup tone.
+	# Play the startup tone.
 	#
 	tune_control play -t 1
 
@@ -224,15 +224,14 @@ else
 	#
 	if param compare SYS_AUTOCONFIG 1
 	then
-		# Wipe out params except RC*, flight modes and total flight time
+		# Wipe out params except RC*, flight modes and total flight time.
 		param reset_nostart RC* COM_FLTMODE* LND_FLIGHT_T_* TC_* CAL_ACC* CAL_GYRO*
 		set AUTOCNF yes
 	else
 		set AUTOCNF no
 
 		#
-		# Release 1.4.0 transitional support:
-		# set to old default if unconfigured,
+		# Release 1.4.0 transitional support: set to old default if unconfigured,
 		# this preserves the previous behaviour.
 		#
 		if param compare BAT_N_CELLS 0
@@ -316,7 +315,7 @@ else
 			param set SYS_FMU_TASK 1
 		fi
 
-		# Disable safety switch by default on Pixracer and OmnibusF4SD
+		# Disable safety switch by default on Pixracer and OmnibusF4SD.
 		if ver hwcmp PX4FMU_V4 OMNIBUS_F4SD
 		then
 			param set CBRK_IO_SAFETY 22027
@@ -351,7 +350,7 @@ else
 
 			if px4io start
 			then
-				# Try to safety px4 io so motor outputs dont go crazy.
+				# Try to safety px4 io so motor outputs don't go crazy.
 				if px4io safety_on
 				then
 					# success! no-op
@@ -405,7 +404,7 @@ else
 
 	#
 	# Sensors System (start before Commander so Preflight checks are properly run).
-	# Commander Needs to be this early for in-air-restarts.
+	# Commander needs to be this early for in-air-restarts.
 	#
 	if param compare SYS_HITL 1
 	then
@@ -527,12 +526,14 @@ else
 		echo "Addons script: ${FEXTRAS}"
 		sh $FEXTRAS
 	fi
-
+#
 # End of autostart.
+#
 fi
 
-# There is no further script processing, so we can free some RAM
-# XXX potentially unset all script variables.
+#
+# Unset all script parameters to free RAM.
+#
 unset AUX_MODE
 unset DATAMAN_OPT
 unset FAILSAFE
@@ -568,6 +569,7 @@ unset PWM_MIN
 unset USE_IO
 unset VEHICLE_TYPE
 
-
+#
 # Boot is complete, inform MAVLink app(s) that the system is now fully up and running.
+#
 mavlink boot_complete