diff --git a/shodan_infrastructure/MpactCheriotCPU.cs b/shodan_infrastructure/MpactCheriotCPU.cs
index dbb7afb..f9e2ef8 100644
--- a/shodan_infrastructure/MpactCheriotCPU.cs
+++ b/shodan_infrastructure/MpactCheriotCPU.cs
@@ -111,10 +111,13 @@
 
     // ICPUSupportingGdb methods.
 
-    public void EnterSingleStepModeSafely(HaltArguments args,
-                                          bool? blocking = null) {
+    public void EnterSingleStepModeSafely(HaltArguments args) {
+        // this method should only be called from CPU thread,
+        // but we should check it anyway
         CheckCpuThreadId();
-        ChangeExecutionModeToSingleStep(blocking);
+
+        ExecutionMode = ExecutionMode.SingleStep;
+
         UpdateHaltedState();
         InvokeHalted(args);
     }