diff --git a/os/sb/host/sbhost.c b/os/sb/host/sbhost.c
index d85c3e0e1..235315ec1 100644
--- a/os/sb/host/sbhost.c
+++ b/os/sb/host/sbhost.c
@@ -203,7 +203,7 @@ bool sbIsThreadRunningX(sb_class_t *sbcp) {
     return false;
   }
 
-  return chThdTerminatedX(sbcp->tp);
+  return !chThdTerminatedX(sbcp->tp);
 }
 
 #if (CH_CFG_USE_WAITEXIT == TRUE) || defined(__DOXYGEN__)