diff --git a/wbsio_spi.c b/wbsio_spi.c
index 28b568e..f4f6af9 100644
--- a/wbsio_spi.c
+++ b/wbsio_spi.c
@@ -115,7 +115,7 @@
 				  const unsigned char *writearr,
 				  unsigned char *readarr)
 {
-	int i;
+	unsigned int i;
 	uint8_t mode = 0;
 
 	msg_pspew("%s:", __func__);