diff --git a/Makefile b/Makefile
index 1f7f12d..98bafdd 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,7 @@ ifeq ($(OS),Windows_NT)
     RM  := del /q
     COM := COM3
 else
-    RM =: rm -rf
+    RM   := rm -rf
 
     UNAME_S := $(shell cat /etc/*-release | grep 'DISTRIB_ID' | sed 's/DISTRIB_ID=\(\w*\)/\1/g')
     ifeq ($(UNAME_S),Ubuntu)
@@ -14,6 +14,7 @@ else
     CC  := ablrun sdcc
     COM := /dev/ttyUSB0
     endif
+    TEMP := $(shell sudo chmod 777 $(COM))
 endif
 
 # set CC TOOL
@@ -48,7 +49,7 @@ uart_temp.hex: $(TARGET)
 	-$(PACKIHX) $(TARGET) > uart_temp.hex
 
 flash: 
-	-stcgal -P stc89 -p $(COM) -d uart_temp.hex
+	-stcgal -P stc89 -p $(COM) uart_temp.hex
 
 #led.bin:led.hex
 #       objcopy -I ihex -O binary led.hex led.bin