diff --git a/cpu/6502/Makefile.6502 b/cpu/6502/Makefile.6502
index 14c252675..9ae7549ae 100644
--- a/cpu/6502/Makefile.6502
+++ b/cpu/6502/Makefile.6502
@@ -64,7 +64,7 @@ AR = ar65
 # The apps coming with Contiki run even on a 0x100 byte stack.
 
 ASFLAGS = -t $(TARGET)
-CFLAGS += -t $(TARGET) -Or
+CFLAGS += -t $(TARGET) -Or -W -unused-param,-unused-var,-const-comparison
 LDFLAGS = $(STARTADDR_FLAG) -t $(TARGET) -m contiki-$(TARGET).map -D __STACKSIZE__=0x200
 AROPTS  = a