diff --git a/build.mk b/build.mk
index 26dc190..7ef061a 100644
--- a/build.mk
+++ b/build.mk
@@ -142,16 +142,16 @@
 else
 	$(CC) -o $(OUTDIR)/$(TARGET_VER).elf $(ALLOBJS) $(LIBS) $(LDFLAGS)
 endif
-ifndef NO_SYM
+ifeq ($(GEN_SYM), yes)
 	$(NM) -t d -S --size-sort $(OUTDIR)/$(TARGET_VER).elf > $(OUTDIR)/$(TARGET_VER).sym
 endif
-ifndef NO_LST
+ifeq ($(GEN_LST), yes)
 	$(OBJDUMP) -xds -S -l $(OUTDIR)/$(TARGET_VER).elf > $(OUTDIR)/$(TARGET_VER).lst
 endif
 ifeq ($(RELEASE), yes)
 	$(STRIP) --strip-debug --strip-unneeded $(OUTDIR)/$(TARGET_VER).elf
 endif
-ifndef NO_SIZE
+ifeq ($(GEN_SIZE), yes)
 	@$(SIZE) -A -d $(OUTDIR)/$(TARGET_VER).elf
 endif
 	$(EMPTY_LINE)
@@ -160,10 +160,10 @@
 $(OUTDIR)/$(TARGET_VER).a: $(MAKEFILE_LIST) $(ALLOBJS) | $(OUTDIR)/
 	@$(ECHO) "Creating static library ..."
 	$(AR) rcs $(OUTDIR)/$(TARGET_VER).a $(ALLOBJS)
-ifndef NO_SYM
+ifeq ($(GEN_SYM), yes)
 	$(NM) -t d -S --size-sort $(OUTDIR)/$(TARGET_VER).a > $(OUTDIR)/$(TARGET_VER)_a.sym
 endif
-ifndef NO_LST
+ifeq ($(GEN_LST), yes)
 	$(OBJDUMP) -xds -S -l $(OUTDIR)/$(TARGET_VER).a > $(OUTDIR)/$(TARGET_VER)_a.lst
 endif
 ifeq ($(RELEASE), yes)
@@ -179,10 +179,10 @@
 else
 	$(CC) -o $(OUTDIR)/$(TARGET_VER).so $(ALLOBJS) $(LIBS) $(LDFLAGS) -rdynamic -shared -Wl,-soname,$(TARGET).so
 endif
-ifndef NO_SYM
+ifeq ($(GEN_SYM), yes)
 	$(NM) -t d -S --size-sort $(OUTDIR)/$(TARGET_VER).so > $(OUTDIR)/$(TARGET_VER)_so.sym
 endif
-ifndef NO_LST
+ifeq ($(GEN_LST), yes)
 	$(OBJDUMP) -xds -S -l $(OUTDIR)/$(TARGET_VER).so > $(OUTDIR)/$(TARGET_VER)_so.lst
 endif
 ifeq ($(RELEASE), yes)