diff --git a/lte/alt1250/alt1250_usockif.c b/lte/alt1250/alt1250_usockif.c
index 825361e7a2..5ca53711d5 100644
--- a/lte/alt1250/alt1250_usockif.c
+++ b/lte/alt1250/alt1250_usockif.c
@@ -257,6 +257,9 @@ int usockif_readreqioctl(int fd, FAR struct usrsock_request_buff_s *buf)
 
   switch (req->cmd)
     {
+      case FIONBIO:
+        rsize = sizeof(int);
+        break;
       case SIOCLTECMD:
         rsize = sizeof(struct lte_ioctl_data_s);
         break;
diff --git a/lte/alt1250/usock_handlers/alt1250_ioctlhdlr.c b/lte/alt1250/usock_handlers/alt1250_ioctlhdlr.c
index 221fc25b05..56d0a4b27f 100644
--- a/lte/alt1250/usock_handlers/alt1250_ioctlhdlr.c
+++ b/lte/alt1250/usock_handlers/alt1250_ioctlhdlr.c
@@ -63,6 +63,11 @@ int usockreq_ioctl(FAR struct alt1250_s *dev,
     {
       switch (request->cmd)
         {
+          case FIONBIO:
+            /* ALT1250 doesn't use this command. Only return OK. */
+
+            *usock_result = OK;
+            break;
           case SIOCLTECMD:
             ioctl_subhdlr = usockreq_ioctl_ltecmd;
             break;