diff --git a/src/hardware/siglent-sds/protocol.c b/src/hardware/siglent-sds/protocol.c
index af2f2d9b..584e5330 100644
--- a/src/hardware/siglent-sds/protocol.c
+++ b/src/hardware/siglent-sds/protocol.c
@@ -544,7 +544,7 @@ SR_PRIV int siglent_sds_receive(int fd, int revents, void *cb_data)
 				sdi->driver->dev_acquisition_stop(sdi);
 				return TRUE;
 			}
-			devc->num_block_bytes = len;
+			devc->num_block_bytes = 0;
 			devc->num_block_read = 0;
 
 			if (len == -1) {
@@ -608,7 +608,7 @@ SR_PRIV int siglent_sds_receive(int fd, int revents, void *cb_data)
 					g_array_free(data, TRUE);
 				}
 				len = 0;
-				if (devc->num_samples == (devc->num_block_bytes - SIGLENT_HEADER_SIZE)) {
+				if (devc->num_samples == devc->num_block_bytes) {
 					sr_dbg("Transfer has been completed.");
 					devc->num_header_bytes = 0;
 					devc->num_block_bytes = 0;