diff --git a/sw/airborne/modules/datalink/missionlib/blocks.c b/sw/airborne/modules/datalink/missionlib/blocks.c
index 1f264cb18f..d172ac351a 100644
--- a/sw/airborne/modules/datalink/missionlib/blocks.c
+++ b/sw/airborne/modules/datalink/missionlib/blocks.c
@@ -50,9 +50,12 @@ void mavlink_send_block(uint16_t seq)
     static const char *blocks[] = FP_BLOCKS;
     char block_name[50];
     strncpy(block_name, blocks[seq], 49); // String containing the name of the block
-    uint8_t len = strlen(blocks[seq]); // Length of the block name
+    uint8_t _terminate = strlen(blocks[seq]); // Length of the block name
+    if (_terminate > 49)
+      _terminate = 49;
+    block_name[_terminate] = 0;
     mavlink_msg_script_item_send(MAVLINK_COMM_0, mission_mgr.rem_sysid, mission_mgr.rem_compid,
-                                 seq, len, block_name);
+                                 seq, block_name);
     MAVLinkSendMessage();
     MAVLINK_DEBUG("Sent BLOCK_ITEM message: seq %i, name %s\n", seq, block_name);
   } else {