diff --git a/lib/drivers/spi/bitbang/lws-bb-spi.c b/lib/drivers/spi/bitbang/lws-bb-spi.c
index 285e53ac5..10f9bc598 100644
--- a/lib/drivers/spi/bitbang/lws-bb-spi.c
+++ b/lib/drivers/spi/bitbang/lws-bb-spi.c
@@ -74,7 +74,8 @@ lws_bb_spi_write(lws_bb_spi_t *ctx, const uint8_t *buf, size_t len)
 static void
 lws_bb_spi_read(lws_bb_spi_t *ctx, uint8_t *buf, size_t len)
 {
-	uint8_t u, inv = !!(ctx->bb_ops.bus_mode & LWSSPIMODE_CPOL);
+	uint8_t u = 0;
+	uint8_t inv = !!(ctx->bb_ops.bus_mode & LWSSPIMODE_CPOL);
 
 	while (len--) {
 		int n;