diff --git a/utility/rtos_compatibility_layers/posix/px_mq_send.c b/utility/rtos_compatibility_layers/posix/px_mq_send.c
index d4702808..f641419a 100644
--- a/utility/rtos_compatibility_layers/posix/px_mq_send.c
+++ b/utility/rtos_compatibility_layers/posix/px_mq_send.c
@@ -167,7 +167,16 @@ ULONG               msg[TX_POSIX_MESSAGE_SIZE];
 
     if (temp1 != TX_SUCCESS)
     {
-    posix_internal_error(9999);
+        posix_internal_error(9999);
+
+        /* posix_internal_error() does not return today, but do not depend on
+           that: bp is indeterminate here, so falling through would copy
+           msg_len bytes through an unset pointer.  */
+        posix_errno = ENOMEM;
+        posix_set_pthread_errno(ENOMEM);
+
+        /* Return ERROR.  */
+        return(ERROR);
     }
     /* Got the memory , Setup source and destination pointers
        Cast them in UCHAR as message length is in bytes.  */
diff --git a/utility/rtos_compatibility_layers/posix/px_pth_init.c b/utility/rtos_compatibility_layers/posix/px_pth_init.c
index 5d2f36ad..a2f97be7 100644
--- a/utility/rtos_compatibility_layers/posix/px_pth_init.c
+++ b/utility/rtos_compatibility_layers/posix/px_pth_init.c
@@ -538,7 +538,13 @@ POSIX_TCB          *p_tcb;
     if (!thread_ptr)
     {
         /* Not called from a thread - error!  */
-           posix_internal_error(222);
+        posix_internal_error(222);
+
+        /* posix_internal_error() does not return today, but do not depend on
+           that: posix_thread2tcb() hands back NULL for this input and the read
+           below would dereference it. A pthread ID is the address of the TCB,
+           so zero is never a valid one.  */
+        return((pthread_t) 0);
     }
 
     /* Get the TCB for this pthread */