diff --git a/drivers/tpm/tpm_tis_sandbox.c b/drivers/tpm/tpm_tis_sandbox.c
index 4aade565e2..e7746dc675 100644
--- a/drivers/tpm/tpm_tis_sandbox.c
+++ b/drivers/tpm/tpm_tis_sandbox.c
@@ -214,9 +214,9 @@ static int sandbox_tpm_xfer(struct udevice *dev, const uint8_t *sendbuf,
 
 			data = recvbuf + TPM_RESPONSE_HEADER_LENGTH +
 					sizeof(uint32_t);
+			memset(&rsk, 0, sizeof(struct rollback_space_kernel));
 			rsk.struct_version = 2;
 			rsk.uid = ROLLBACK_SPACE_KERNEL_UID;
-			rsk.kernel_versions = 0;
 			rsk.crc8 = crc8(0, (unsigned char *)&rsk,
 					offsetof(struct rollback_space_kernel,
 						 crc8));