diff --git a/src/emucore/M6502.cxx b/src/emucore/M6502.cxx
index ba0387944..58166c59b 100644
--- a/src/emucore/M6502.cxx
+++ b/src/emucore/M6502.cxx
@@ -20,6 +20,8 @@
   #include "Expression.hxx"
   #include "CartDebug.hxx"
   #include "PackedBitArray.hxx"
+  #include "TIA.hxx"
+  #include "M6532.hxx"
 
   // Flags for disassembly types
   #define DISASM_CODE  CartDebug::CODE
@@ -65,7 +67,8 @@ M6502::M6502(const Settings& settings)
     myLastSrcAddressY(-1),
     myDataAddressForPoke(0),
     myOnHaltCallback(nullptr),
-    myHaltRequested(false)
+    myHaltRequested(false),
+    myStepStateByInstruction(false)
 {
 #ifdef DEBUGGER_SUPPORT
   myDebugger = nullptr;
@@ -197,12 +200,23 @@ inline void M6502::handleHalt()
   }
 }
 
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+void M6502::updateStepStateByInstruction()
+{
+  myStepStateByInstruction = myCondBreaks.size() || myCondSaveStates.size() || myTrapConds.size();
+}
+
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 bool M6502::execute(uInt32 number)
 {
   // Clear all of the execution status bits except for the fatal error bit
   myExecutionStatus &= FatalErrorBit;
 
+#ifdef DEBUGGER_SUPPORT
+  TIA& tia = mySystem->tia();
+  M6532& riot = mySystem->m6532();
+#endif
+
   // Loop until execution is stopped or a fatal error occurs
   for(;;)
   {
@@ -258,6 +272,13 @@ bool M6502::execute(uInt32 number)
           myExecutionStatus |= FatalErrorBit;
       }
       //cycles = mySystem->cycles() - c0;
+
+#ifdef DEBUGGER_SUPPORT
+      if (myStepStateByInstruction) {
+        tia.updateEmulation();
+        riot.updateEmulation();
+      }
+#endif
     }
 
     // See if we need to handle an interrupt
@@ -367,6 +388,7 @@ bool M6502::save(Serializer& out) const
     out.putInt(myLastSrcAddressY);
 
     out.putBool(myHaltRequested);
+    out.putBool(myStepStateByInstruction);
   }
   catch(...)
   {
@@ -417,6 +439,7 @@ bool M6502::load(Serializer& in)
     myLastSrcAddressY = in.getInt();
 
     myHaltRequested = in.getBool();
+    myStepStateByInstruction = in.getBool();
   }
   catch(...)
   {
@@ -440,6 +463,9 @@ uInt32 M6502::addCondBreak(Expression* e, const string& name)
 {
   myCondBreaks.emplace_back(e);
   myCondBreakNames.push_back(name);
+
+  updateStepStateByInstruction();
+
   return uInt32(myCondBreaks.size() - 1);
 }
 
@@ -450,6 +476,9 @@ bool M6502::delCondBreak(uInt32 idx)
   {
     Vec::removeAt(myCondBreaks, idx);
     Vec::removeAt(myCondBreakNames, idx);
+
+    updateStepStateByInstruction();
+
     return true;
   }
   return false;
@@ -460,6 +489,8 @@ void M6502::clearCondBreaks()
 {
   myCondBreaks.clear();
   myCondBreakNames.clear();
+
+  updateStepStateByInstruction();
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -473,6 +504,9 @@ uInt32 M6502::addCondSaveState(Expression* e, const string& name)
 {
   myCondSaveStates.emplace_back(e);
   myCondSaveStateNames.push_back(name);
+
+  updateStepStateByInstruction();
+
   return uInt32(myCondSaveStates.size() - 1);
 }
 
@@ -483,6 +517,9 @@ bool M6502::delCondSaveState(uInt32 idx)
   {
     Vec::removeAt(myCondSaveStates, idx);
     Vec::removeAt(myCondSaveStateNames, idx);
+
+    updateStepStateByInstruction();
+
     return true;
   }
   return false;
@@ -493,6 +530,8 @@ void M6502::clearCondSaveStates()
 {
   myCondSaveStates.clear();
   myCondSaveStateNames.clear();
+
+  updateStepStateByInstruction();
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -506,6 +545,9 @@ uInt32 M6502::addCondTrap(Expression* e, const string& name)
 {
   myTrapConds.emplace_back(e);
   myTrapCondNames.push_back(name);
+
+  updateStepStateByInstruction();
+
   return uInt32(myTrapConds.size() - 1);
 }
 
@@ -516,6 +558,9 @@ bool M6502::delCondTrap(uInt32 brk)
   {
     Vec::removeAt(myTrapConds, brk);
     Vec::removeAt(myTrapCondNames, brk);
+
+    updateStepStateByInstruction();
+
     return true;
   }
   return false;
@@ -526,6 +571,8 @@ void M6502::clearCondTraps()
 {
   myTrapConds.clear();
   myTrapCondNames.clear();
+
+  updateStepStateByInstruction();
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
diff --git a/src/emucore/M6502.hxx b/src/emucore/M6502.hxx
index 16feb2459..c00d22d85 100644
--- a/src/emucore/M6502.hxx
+++ b/src/emucore/M6502.hxx
@@ -312,6 +312,12 @@ class M6502 : public Serializable
     */
     void handleHalt();
 
+    /**
+      Check whether we are required to update hardware (TIA + RIOT) in lockstep
+      with the CPU and update the flag accordingly.
+    */
+    void updateStepStateByInstruction();
+
   private:
     /**
       Bit fields used to indicate that certain conditions need to be
@@ -439,6 +445,8 @@ class M6502 : public Serializable
     vector<unique_ptr<Expression>> myTrapConds;
     StringList myTrapCondNames;
 
+    bool myStepStateByInstruction;
+
 #endif  // DEBUGGER_SUPPORT
 
   private:
diff --git a/src/emucore/M6532.hxx b/src/emucore/M6532.hxx
index ebd298d33..e235fb606 100644
--- a/src/emucore/M6532.hxx
+++ b/src/emucore/M6532.hxx
@@ -125,13 +125,16 @@ class M6532 : public Device
     */
     bool poke(uInt16 address, uInt8 value) override;
 
+    /**
+     * Update RIOT state to the current timestamp.
+     */
+    void updateEmulation();
+
   private:
 
     void setTimerRegister(uInt8 data, uInt8 interval);
     void setPinState(bool shcha);
 
-    void updateEmulation();
-
     // The following are used by the debugger to read INTIM/TIMINT
     // We need separate methods to do this, so the state of the system
     // isn't changed
diff --git a/src/emucore/tia/TIA.hxx b/src/emucore/tia/TIA.hxx
index a64b726e6..85fb673c4 100644
--- a/src/emucore/tia/TIA.hxx
+++ b/src/emucore/tia/TIA.hxx
@@ -443,6 +443,11 @@ class TIA : public Device
     */
     string name() const override { return "TIA"; }
 
+    /**
+     * Run and forward TIA emulation to the current system clock.
+     */
+    void updateEmulation();
+
   private:
     /**
      * During each line, the TIA cycles through these two states.
@@ -481,11 +486,6 @@ class TIA : public Device
      */
     void onHalt();
 
-    /**
-     * Run and forward TIA emulation to the current system clock.
-     */
-    void updateEmulation();
-
     /**
      * Execute colorClocks cycles of TIA simulation.
      */