diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/GBHawk.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/GBHawk.cs
index ee2306459e..411b53c989 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/GBHawk.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/GBHawk.cs
@@ -130,7 +130,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 
 		[CoreConstructor(VSystemID.Raw.GB)]
 		[CoreConstructor(VSystemID.Raw.GBC)]
-		public GBHawk(CoreComm comm, GameInfo game, byte[] rom, /*string gameDbFn,*/ GBSettings settings, GBSyncSettings syncSettings)
+		public GBHawk(CoreComm comm, GameInfo game, byte[] rom, /*string gameDbFn,*/ GBSettings settings, GBSyncSettings syncSettings, bool subframe = false)
 		{
 			var ser = new BasicServiceProvider(this);
 
@@ -199,7 +199,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 
 			_controllerDeck = new(mppr is "MBC7"
 				? typeof(StandardTilt).DisplayName()
-				: GBHawkControllerDeck.DefaultControllerName);
+				: GBHawkControllerDeck.DefaultControllerName, subframe);
 
 			timer.Core = this;
 			audio.Core = this;
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/GBHawkControllerDeck.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/GBHawkControllerDeck.cs
index 936cacb418..7353fb9897 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/GBHawkControllerDeck.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/GBHawkControllerDeck.cs
@@ -10,7 +10,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 {
 	public class GBHawkControllerDeck
 	{
-		public GBHawkControllerDeck(string controller1Name)
+		public GBHawkControllerDeck(string controller1Name, bool subframe)
 		{
 			Port1 = ControllerCtors.TryGetValue(controller1Name, out var ctor1)
 				? ctor1(1)
@@ -24,6 +24,11 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 
 			foreach (var kvp in Port1.Definition.Axes) Definition.Axes.Add(kvp);
 
+			if (subframe)
+			{
+				Definition.AddAxis("Input Cycle", 0.RangeTo(70224), 70224);
+			}
+
 			Definition.MakeImmutable();
 		}
 
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.Core.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.Core.cs
index b5a3d968ec..8a64289b73 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.Core.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.Core.cs
@@ -88,7 +88,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 
 		public bool CanProvideAsync => false;
 
-		internal void ResetControllerDefinition()
+		internal void ResetControllerDefinition(bool subframe)
 		{
 			ControllerDefinition = null;
 
@@ -115,7 +115,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 			}
 
 			// Add in the reset timing axis for subneshawk
-			if (using_reset_timing && ControllerDefinition.Axes.Count == 0)
+			if (subframe)
 			{
 				ControllerDefinition.AddAxis("Reset Cycle", 0.RangeTo(500000), 0);
 			}
@@ -398,8 +398,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 		public bool current_strobe;
 		public bool new_strobe;
 		public bool alt_lag;
-		// variable used with subneshawk to trigger reset at specific cycle after reset
-		public bool using_reset_timing = false;
+
 		// this function will run one step of the ppu 
 		// it will return whether the controller is read or not.
 		public void do_single_step(IController controller, out bool cont_read, out bool frame_done)
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.cs
index a40c3f34a5..cc80535ac6 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.cs
@@ -14,7 +14,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 		IBoardInfo, IRomInfo, ISettable<NES.NESSettings, NES.NESSyncSettings>, ICodeDataLogger
 	{
 		[CoreConstructor(VSystemID.Raw.NES)]
-		public NES(CoreComm comm, GameInfo game, byte[] rom, NESSettings settings, NESSyncSettings syncSettings)
+		public NES(CoreComm comm, GameInfo game, byte[] rom, NESSettings settings, NESSyncSettings syncSettings, bool subframe = false)
 		{
 			var ser = new BasicServiceProvider(this);
 			ServiceProvider = ser;
@@ -71,7 +71,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 				}
 			}
 
-			ResetControllerDefinition();
+			ResetControllerDefinition(subframe);
 		}
 
 		private static readonly bool USE_DATABASE = true;
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/SubGBHawk/SubGBHawk.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/SubGBHawk/SubGBHawk.cs
index 9384b1ab4d..561ad6a3bd 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/SubGBHawk/SubGBHawk.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/SubGBHawk/SubGBHawk.cs
@@ -19,7 +19,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.SubGBHawk
 			var subGBSettings = (GBHawk.GBHawk.GBSettings)settings ?? new GBHawk.GBHawk.GBSettings();
 			var subGBSyncSettings = (GBHawk.GBHawk.GBSyncSettings)syncSettings ?? new GBHawk.GBHawk.GBSyncSettings();
 
-			_GBCore = new GBHawk.GBHawk(comm, game, rom, subGBSettings, subGBSyncSettings);
+			_GBCore = new GBHawk.GBHawk(comm, game, rom, subGBSettings, subGBSyncSettings, true);
 
 			HardReset();
 			current_cycle = 0;
@@ -41,9 +41,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.SubGBHawk
 
 			_tracer = new TraceBuffer(_GBCore.cpu.TraceHeader);
 			ser.Register(_tracer);
-
-			_GBCore.ControllerDefinition.AddAxis("Input Cycle", 0.RangeTo(70224), 70224)
-				.MakeImmutable();
 		}
 
 		public GBHawk.GBHawk _GBCore;
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/SubNESHawk/SubNESHawk.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/SubNESHawk/SubNESHawk.cs
index d7a6d0dc93..76bdd77f52 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/SubNESHawk/SubNESHawk.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/SubNESHawk/SubNESHawk.cs
@@ -14,13 +14,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.SubNESHawk
 			var subNesSettings = (NES.NES.NESSettings)settings ?? new NES.NES.NESSettings();
 			var subNesSyncSettings = (NES.NES.NESSyncSettings)syncSettings ?? new NES.NES.NESSyncSettings();
 
-			_nesCore = new NES.NES(comm, game, rom, subNesSettings, subNesSyncSettings)
-			{
-				using_reset_timing = true
-			};
-
-			// Adds Reset timing control to controller definition
-			_nesCore.ResetControllerDefinition();
+			_nesCore = new NES.NES(comm, game, rom, subNesSettings, subNesSyncSettings, true);
 
 			HardReset();
 			current_cycle = 0;