diff --git a/sensorhandler.cpp b/sensorhandler.cpp
index d8cd0d4..53eb6d6 100644
--- a/sensorhandler.cpp
+++ b/sensorhandler.cpp
@@ -639,6 +639,7 @@
     // A constant reservation ID is okay until we implement add/remove SDR.
     const uint16_t reservation_id = 1;
     *(uint16_t*)response = reservation_id;
+    *data_len = sizeof(uint16_t);
 
     printf("Created new IPMI SDR reservation ID %d\n", *(uint16_t*)response);
     return IPMI_CC_OK;