diff --git a/Makefile b/Makefile
index f8631ecdc2c18cff69017c3d960f9e16055aeca6..b8d9c0edff241cf6a787292d409dae68d146eaca 100644
--- a/Makefile
+++ b/Makefile
@@ -27,7 +27,7 @@ all: $(BIN)
 	$(CC) -o $@ $^ $(CFLAGS) $(OMPSS_FLAGS) $(LIBS)
 
 matmul_block.$(BS)bs.o : matmul_block.c
-	$(CC) -c $^ -o $@ $(CPPFLAGS) $(CFLAGS) $(BLAS_CPPFLAGS) $(BLAS_LDFLAGS)
+	$(CC) -c $^ -o $@ $(CPPFLAGS) $(CFLAGS) -DBS=$(BS) $(BLAS_CPPFLAGS) $(BLAS_LDFLAGS)
 
 04.matmul% : 04.matmul%.c main.c matmul_block.$(BS)bs.o
 	$(CC) -o $@ $^ $(CFLAGS) $(OMPSS_FLAGS) -DBS=$(BS) $(LIBS)
@@ -39,4 +39,4 @@ run: $(BIN)
 	./04.matmul_taskloop+dep $(N) $(M) $(P) $(BLOCK_SIZE)
 
 clean:
-	$(RM) $(BIN)
+	$(RM) $(BIN) matmul_block.$(BS)bs.o