diff --git a/src/drivers/spi/tpm/tpm.c b/src/drivers/spi/tpm/tpm.c
index 08e1c4e..e6a88c6 100644
--- a/src/drivers/spi/tpm/tpm.c
+++ b/src/drivers/spi/tpm/tpm.c
@@ -237,6 +237,7 @@
 	do {
 		if (stopwatch_expired(&sw)) {
 			printk(BIOS_ERR, "TPM flow control failure\n");
+			tpm_if.cs_deassert(tpm_if.slave);
 			return 0;
 		}
 		tpm_if.xfer(tpm_if.slave, NULL, 0, &byte, 1);