diff --git a/Grow.c b/Grow.c
index 8df4ac4..046b23d 100644
--- a/Grow.c
+++ b/Grow.c
@@ -174,7 +174,7 @@ int Grow_Add_device(char *devname, int fd, char *newdev)
 			return 1;
 		}
 		fd2 = dev_open(dv, O_RDWR);
-		if (!fd2) {
+		if (fd2 < 0) {
 			fprintf(stderr, Name ": cannot open device file %s\n", dv);
 			close(nfd);
 			free(st);