diff --git a/Arduino.mk b/Arduino.mk
index debd32d..936645a 100644
--- a/Arduino.mk
+++ b/Arduino.mk
@@ -1296,7 +1296,8 @@ ifdef AVRDUDE_CONF
 endif
 
 # -D - Disable auto erase for flash memory
-# -D is needed for Mega boards. (See https://github.com/sudar/Arduino-Makefile/issues/114#issuecomment-25011005)
+# Note: -D is needed for Mega boards.
+#       (See https://github.com/sudar/Arduino-Makefile/issues/114#issuecomment-25011005)
 AVRDUDE_ARD_OPTS = -D -c $(AVRDUDE_ARD_PROGRAMMER) -b $(AVRDUDE_ARD_BAUDRATE) -P
 ifeq ($(CURRENT_OS), WINDOWS)
     # get_monitor_port checks to see if the monitor port exists, assuming it is
@@ -1361,7 +1362,9 @@ ifndef AVRDUDE_ISP_FUSES_POST
     endif
 endif
 
-# -D may cause issues with some boards like attiny84a.
+# Note: setting -D to disable flash erase before programming may cause issues
+# with some boards like attiny84a, making the program not "take",
+# so we do not set it by default.
 AVRDUDE_ISP_OPTS = -c $(ISP_PROG) -b $(AVRDUDE_ISP_BAUDRATE)
 
 ifndef $(ISP_PORT)