diff --git a/lib/tpm-v1.c b/lib/tpm-v1.c
index 22a769c587..d0e3ab1b21 100644
--- a/lib/tpm-v1.c
+++ b/lib/tpm-v1.c
@@ -456,12 +456,13 @@ u32 tpm1_get_permissions(struct udevice *dev, u32 index, u32 *perm)
 		0x0, 0x0, 0x0, 0x4,
 	};
 	const size_t index_offset = 18;
-	const size_t perm_offset = 60;
+	const size_t perm_offset = 74;
 	u8 buf[COMMAND_BUFFER_SIZE], response[COMMAND_BUFFER_SIZE];
 	size_t response_length = sizeof(response);
 	u32 err;
 
-	if (pack_byte_string(buf, sizeof(buf), "d", 0, command, sizeof(command),
+	if (pack_byte_string(buf, sizeof(buf), "sd",
+			     0, command, sizeof(command),
 			     index_offset, index))
 		return TPM_LIB_ERROR;
 	err = tpm_sendrecv_command(dev, buf, response, &response_length);