diff --git a/py/lexerunix.c b/py/lexerunix.c
index ac07781b5a..80daf6009a 100644
--- a/py/lexerunix.c
+++ b/py/lexerunix.c
@@ -48,8 +48,13 @@ mp_lexer_t *mp_lexer_new_from_file(const char *filename) {
     uint size = lseek(fd, 0, SEEK_END);
     lseek(fd, 0, SEEK_SET);
     char *data = m_new(char, size);
-    read(fd, data, size);
+    int read_size = read(fd, data, size);
     close(fd);
+    if (read_size != size) {
+        printf("error reading file %s\n", filename);
+        m_free(data);
+        return NULL;
+    }
 
     return mp_lexer_new_from_str_len(filename, data, size, true);
 }
diff --git a/unix/Makefile b/unix/Makefile
index 441804e509..91e26e5247 100644
--- a/unix/Makefile
+++ b/unix/Makefile
@@ -65,7 +65,7 @@ $(PROG): $(BUILD) $(OBJ)
 	size $(PROG)
 
 $(BUILD):
-	mkdir $@
+	mkdir -p $@
 
 $(BUILD)/%.o: %.c
 	$(CC) $(CFLAGS) -c -o $@ $<