diff --git a/software/bios/Makefile b/software/bios/Makefile
index 4d4fcdd4c..bfd0aafa5 100644
--- a/software/bios/Makefile
+++ b/software/bios/Makefile
@@ -24,6 +24,9 @@ bios-rescue.elf: linker-rescue.ld $(OBJECTS) libs
 		-lbase -lcompiler_rt
 	chmod -x $@
 
+%.o: %.c
+	$(compile-dep)
+
 libs:
 	make -C $(M2DIR)/software/libbase
 
diff --git a/software/common.mak b/software/common.mak
index 45dffd6d1..046557a9f 100644
--- a/software/common.mak
+++ b/software/common.mak
@@ -37,11 +37,12 @@ LDFLAGS = -nostdlib -nodefaultlibs
 # compile and generate dependencies, based on
 # http://scottmcpeak.com/autodepend/autodepend.html
 
-%.o: $(SRCDIR)%.c
-	$(CC) -c $(CFLAGS) $(SRCDIR)$*.c -o $*.o
-	@$(CC_normal) -MM $(CFLAGS) $(SRCDIR)$*.c > $*.d
-	@mv -f $*.d $*.d.tmp
-	@sed -e 's|.*:|$*.o:|' < $*.d.tmp > $*.d
-	@sed -e 's/.*://' -e 's/\\$$//' < $*.d.tmp | fmt -1 | \
-	  sed -e 's/^ *//' -e 's/$$/:/' >> $*.d
-	@rm -f $*.d.tmp
+define compile-dep =
+$(CC) -c $(CFLAGS) $< -o $*.o
+@$(CC_normal) -MM $(CFLAGS) $< > $*.d
+@mv -f $*.d $*.d.tmp
+@sed -e 's|.*:|$*.o:|' < $*.d.tmp > $*.d
+@sed -e 's/.*://' -e 's/\\$$//' < $*.d.tmp | fmt -1 | \
+	sed -e 's/^ *//' -e 's/$$/:/' >> $*.d
+@rm -f $*.d.tmp
+endef
diff --git a/software/libbase/Makefile b/software/libbase/Makefile
index afa5650f7..5c938db90 100644
--- a/software/libbase/Makefile
+++ b/software/libbase/Makefile
@@ -12,6 +12,9 @@ libbase.a: $(OBJECTS)
 	$(AR) clr libbase.a $(OBJECTS)
 	$(RANLIB) libbase.a
 
+%.o: %.c
+	$(compile-dep)
+
 .PHONY: clean
 
 clean: