diff --git a/src/BizHawk.BizInvoke/BizInvoker.cs b/src/BizHawk.BizInvoke/BizInvoker.cs
index f37d633e01..f6126dc868 100644
--- a/src/BizHawk.BizInvoke/BizInvoker.cs
+++ b/src/BizHawk.BizInvoke/BizInvoker.cs
@@ -486,10 +486,11 @@ namespace BizHawk.BizInvoke
 
 			if (type.IsByRef)
 			{
+				// Just pass a raw pointer.  In the `ref structType` case, caller needs to ensure fields are compatible.
 				var et = type.GetElementType()!;
-				if (!et.IsPrimitive && !et.IsEnum)
+				if (!et.IsValueType)
 				{
-					throw new NotImplementedException("Only refs of primitive or enum types are supported!");
+					throw new NotImplementedException("Only refs of value types are supported!");
 				}
 				return new(
 					typeof(IntPtr),
@@ -642,6 +643,7 @@ namespace BizHawk.BizInvoke
 			if (type.IsClass)
 			{
 				// non ref of class can just be passed as pointer
+				// Just like in the `ref struct` case, if the fields aren't compatible, that's the caller's problem.
 				return new(
 					typeof(IntPtr),
 					() =>
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/BsnesApi.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/BsnesApi.cs
index d40efde9fc..f8e4714069 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/BsnesApi.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/BsnesApi.cs
@@ -18,7 +18,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 		[BizImport(CallingConvention.Cdecl)]
 		public abstract void snes_set_video_enabled(bool enabled);
 		[BizImport(CallingConvention.Cdecl)]
-		public abstract void snes_set_layer_enables(BsnesApi.LayerEnables layerEnables);
+		public abstract void snes_set_layer_enables(ref BsnesApi.LayerEnables layerEnables);
 		[BizImport(CallingConvention.Cdecl)]
 		public abstract void snes_set_trace_enabled(bool enabled);
 
@@ -144,10 +144,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 		public delegate string snes_path_request_t(int slot, string hint, bool required);
 		public delegate void snes_trace_t(string disassembly, string register_info);
 
-
-		// I cannot use a struct here because marshalling is retarded for bool (4 bytes). I honestly cannot
 		[StructLayout(LayoutKind.Sequential)]
-		public class LayerEnables
+		public struct LayerEnables
 		{
 			public bool BG1_Prio0, BG1_Prio1;
 			public bool BG2_Prio0, BG2_Prio1;
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/BsnesCore.IEmulator.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/BsnesCore.IEmulator.cs
index f84c73916d..d00a7190ac 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/BsnesCore.IEmulator.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/BsnesCore.IEmulator.cs
@@ -47,7 +47,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 				Obj_Prio3 = _settings.ShowOBJ_3
 			};
 			// TODO: I really don't think stuff like this should be set every single frame (only on change)
-			Api.core.snes_set_layer_enables(enables);
+			Api.core.snes_set_layer_enables(ref enables);
 			Api.core.snes_set_trace_enabled(_tracer.Enabled);
 			Api.core.snes_set_video_enabled(render);
 			Api.core.snes_set_audio_enabled(renderSound);