Add a comment to explicit the KSM check

platform/kobo/koreader.sh

@@ -87,6 +87,8 @@ if [ "${from_nickel}" == "true" ] ; then
 	./nickel.sh &
 else
 	# if we were called from advboot then we must reboot to go to the menu
+	# NOTE: This is actually achieved by checking if KSM is running:
+	#       This might lead to false-positives if you use neither KSM nor advboot to launch KOReader *without nickel running*.
 	if ! pkill -0 ksmhome.sh ; then
 		reboot
 	fi