for your consideration: sync settings return flags instead of a bool, so we can have more granularity in what needs resetting than just "reboot core". for instance, we would like to minimize the number of times the window layout is redone by not doing it when the screen settings havent changed. HOWEVER, while I was writing this commit message, I realized, I should probably do it just by being more cautious in kicking off the layout (unless the data coming from the core has changed, a layout shouldnt happen). So I am going to make this commit, in case it inspires anyone, and then revert it.

BizHawk.Client.Common/Api/Classes/EmuApi.cs

@@ -195,7 +195,7 @@ namespace BizHawk.Client.Common
 			_ => (object) null
 		};
 
-		public bool PutSettings(object settings) => Emulator switch
+		public PutSettingsDirtyBits PutSettings(object settings) => Emulator switch
 		{
 			GPGX gpgx => gpgx.PutSettings((GPGX.GPGXSettings) settings),
 			LibsnesCore snes => snes.PutSettings((LibsnesCore.SnesSettings) settings),
@@ -204,7 +204,7 @@ namespace BizHawk.Client.Common
 			QuickNES quickNes => quickNes.PutSettings((QuickNES.QuickNESSettings) settings),
 			SMS sms => sms.PutSettings((SMS.SmsSettings) settings),
 			WonderSwan ws => ws.PutSettings((WonderSwan.Settings) settings),
-			_ => false
+			_ => PutSettingsDirtyBits.None
 		};
 
 		public void SetRenderPlanes(params bool[] args)

BizHawk.Client.Common/Api/Interfaces/IEmu.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using BizHawk.Emulation.Common;
 
 namespace BizHawk.Client.Common
 {
@@ -26,7 +27,7 @@ namespace BizHawk.Client.Common
 		string GetDisplayType();
 		string GetBoardName();
 		object GetSettings();
-		bool PutSettings(object settings);
+		PutSettingsDirtyBits PutSettings(object settings);
 		void SetRenderPlanes(params bool[] args);
 	}
 }

BizHawk.Client.EmuHawk/MainForm.cs

@@ -2305,11 +2305,12 @@ namespace BizHawk.Client.EmuHawk
 		public void PutCoreSettings(object o)
 		{
 			var settable = new SettingsAdapter(Emulator);
-			if (settable.HasSettings && settable.PutSettings(o))
+			if (!settable.HasSettings)
-			{
+				return;
+			var dirty = settable.PutSettings(o);
+			if(dirty.HasFlag(PutSettingsDirtyBits.RebootCore))
 				FlagNeedsReboot();
 		}
-		}
 
 		// TODO: Get/Put settings/sync settings methods could become a service we instantiate and use and pass to other forms
 		/// <summary>
@@ -2322,8 +2323,12 @@ namespace BizHawk.Client.EmuHawk
 			{
 				AddOnScreenMessage("Attempt to change sync-relevant settings while recording BLOCKED.");
 			}
-			else if (settable.HasSyncSettings && settable.PutSyncSettings(o))
+			else
 			{
+				if (!settable.HasSyncSettings)
+					return;
+				var dirty = settable.PutSyncSettings(o);
+				if(dirty.HasFlag(PutSettingsDirtyBits.RebootCore))
 					FlagNeedsReboot();
 			}
 		}

BizHawk.Emulation.Common/Interfaces/Services/ISettable.cs

@@ -41,7 +41,7 @@ namespace BizHawk.Emulation.Common
 		/// </summary>
 		/// <param name="o">an object of the same type as the return for GetSettings</param>
 		/// <returns>true if a core reboot will be required to make the changes effective</returns>
-		bool PutSettings(TSettings o);
+		PutSettingsDirtyBits PutSettings(TSettings o);
 
 		/// <summary>
 		/// changes the movie-sync relevant settings.  THIS SHOULD NEVER BE CALLED WHILE RECORDING
@@ -49,7 +49,19 @@ namespace BizHawk.Emulation.Common
 		/// </summary>
 		/// <param name="o">an object of the same type as the return for GetSyncSettings</param>
 		/// <returns>true if a core reboot will be required to make the changes effective</returns>
-		bool PutSyncSettings(TSync o);
+		PutSettingsDirtyBits PutSyncSettings(TSync o);
+	}
+
+	//note: this is a bit of a frail API. If a frontend wants a new flag, cores won't know to yea or nay it
+	//this could be solved by adding a KnownSettingsDirtyBits on the settings interface
+	//or, in a pinch, the same thing could be done with THESE flags, so that the interface doesn't 
+	//change but newly-aware cores can simply manifest that they know about more bits, in the same variable they return the bits in
+	[Flags]
+	public enum PutSettingsDirtyBits
+	{
+		None = 0,
+		RebootCore = 1,
+		ScreenLayoutChanged = 2,
 	}
 
 	/// <summary>
@@ -126,7 +138,7 @@ namespace BizHawk.Emulation.Common
 		}
 
 		/// <exception cref="InvalidOperationException">does not have non-sync settings</exception>
-		public bool PutSettings(object o)
+		public PutSettingsDirtyBits PutSettings(object o)
 		{
 			if (!HasSettings)
 			{
@@ -134,11 +146,11 @@ namespace BizHawk.Emulation.Common
 			}
 
 			_tmp1[0] = o;
-			return (bool)_puts.Invoke(_emu, _tmp1);
+			return (PutSettingsDirtyBits)_puts.Invoke(_emu, _tmp1);
 		}
 
 		/// <exception cref="InvalidOperationException">does not have sync settings</exception>
-		public bool PutSyncSettings(object o)
+		public PutSettingsDirtyBits PutSyncSettings(object o)
 		{
 			if (!HasSyncSettings)
 			{
@@ -146,7 +158,7 @@ namespace BizHawk.Emulation.Common
 			}
 
 			_tmp1[0] = o;
-			return (bool)_putss.Invoke(_emu, _tmp1);
+			return (PutSettingsDirtyBits)_putss.Invoke(_emu, _tmp1);
 		}
 	}
 }

BizHawk.Emulation.Cores/Arcades/MAME/MAME.cs

@@ -257,18 +257,18 @@ namespace BizHawk.Emulation.Cores.Arcades.MAME
 		#region ISettable
 
 		public object GetSettings() => null;
-		public bool PutSettings(object o) => false;
+		public PutSettingsDirtyBits PutSettings(object o) => PutSettingsDirtyBits.None;
 
 		public SyncSettings GetSyncSettings()
 		{
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSyncSettings(SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(SyncSettings o)
 		{
 			bool ret = SyncSettings.NeedsReboot(o, _syncSettings);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		public class SyncSettings

BizHawk.Emulation.Cores/Calculator/TI83.ISettable.cs

@@ -11,10 +11,10 @@ namespace BizHawk.Emulation.Cores.Calculators
 			return _settings.Clone();
 		}
 
-		public bool PutSettings(TI83Settings o)
+		public PutSettingsDirtyBits PutSettings(TI83Settings o)
 		{
 			_settings = o;
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
 		public object GetSyncSettings()
@@ -22,9 +22,9 @@ namespace BizHawk.Emulation.Cores.Calculators
 			return null;
 		}
 
-		public bool PutSyncSettings(object o)
+		public PutSettingsDirtyBits PutSyncSettings(object o)
 		{
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
 		public class TI83Settings

BizHawk.Emulation.Cores/Computers/AmstradCPC/AmstradCPC.ISettable.cs

@@ -25,7 +25,7 @@ namespace BizHawk.Emulation.Cores.Computers.AmstradCPC
 			return SyncSettings.Clone();
 		}
 
-		public bool PutSettings(AmstradCPCSettings o)
+		public PutSettingsDirtyBits PutSettings(AmstradCPCSettings o)
 		{
 
 			// restore user settings to devices
@@ -42,14 +42,14 @@ namespace BizHawk.Emulation.Cores.Computers.AmstradCPC
 
 			Settings = o;
 
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(AmstradCPCSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(AmstradCPCSyncSettings o)
 		{
 			bool ret = AmstradCPCSyncSettings.NeedsReboot(SyncSettings, o);
 			SyncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		public class AmstradCPCSettings

BizHawk.Emulation.Cores/Computers/AppleII/AppleII.ISettable.cs

@@ -20,16 +20,16 @@ namespace BizHawk.Emulation.Cores.Computers.AppleII
 
 		public object GetSyncSettings() => null;
 
-		public bool PutSettings(Settings o)
+		public PutSettingsDirtyBits PutSettings(Settings o)
 		{
 			_settings = o;
 			_machine.Video.IsMonochrome = _settings.Monochrome;
 
 			SetCallbacks();
 
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(object o) => false;
+		public PutSettingsDirtyBits PutSyncSettings(object o) => PutSettingsDirtyBits.None;
 	}
 }

BizHawk.Emulation.Cores/Computers/Commodore64/C64.ISettable.cs

@@ -16,16 +16,16 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64
 			return SyncSettings.Clone();
 		}
 
-		public bool PutSettings(C64Settings o)
+		public PutSettingsDirtyBits PutSettings(C64Settings o)
 		{
 			Settings = o;
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(C64SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(C64SyncSettings o)
 		{
 			SyncSettings = o;
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
 		internal C64Settings Settings { get; private set; }

BizHawk.Emulation.Cores/Computers/MSX/MSX.ISettable.cs

@@ -16,18 +16,18 @@ namespace BizHawk.Emulation.Cores.Computers.MSX
 			return SyncSettings.Clone();
 		}
 
-		public bool PutSettings(MSXSettings o)
+		public PutSettingsDirtyBits PutSettings(MSXSettings o)
 		{
 			bool ret = MSXSettings.RebootNeeded(Settings, o);
 			Settings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(MSXSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(MSXSyncSettings o)
 		{
 			bool ret = MSXSyncSettings.RebootNeeded(SyncSettings, o);
 			SyncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		internal MSXSettings Settings { get; private set; }

BizHawk.Emulation.Cores/Computers/SinclairSpectrum/ZXSpectrum.ISettable.cs

@@ -20,7 +20,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 
 		public ZXSpectrumSyncSettings GetSyncSettings() => SyncSettings.Clone();
 
-		public bool PutSettings(ZXSpectrumSettings o)
+		public PutSettingsDirtyBits PutSettings(ZXSpectrumSettings o)
 		{
 			// restore user settings to devices
 			if (_machine?.AYDevice != null)
@@ -39,14 +39,14 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 
 			Settings = o;
 
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(ZXSpectrumSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(ZXSpectrumSyncSettings o)
 		{
 			bool ret = ZXSpectrumSyncSettings.NeedsReboot(SyncSettings, o);
 			SyncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		public class ZXSpectrumSettings

BizHawk.Emulation.Cores/Consoles/Atari/2600/Atari2600.ISettable.cs

@@ -21,7 +21,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 			return SyncSettings.Clone();
 		}
 
-		public bool PutSettings(A2600Settings o)
+		public PutSettingsDirtyBits PutSettings(A2600Settings o)
 		{
 			if (Settings == null || Settings.SECAMColors != o.SECAMColors)
 			{
@@ -29,14 +29,14 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 			}
 
 			Settings = o;
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(A2600SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(A2600SyncSettings o)
 		{
 			bool ret = A2600SyncSettings.NeedsReboot(SyncSettings, o);
 			SyncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		internal A2600Settings Settings { get; private set; }

BizHawk.Emulation.Cores/Consoles/Atari/A7800Hawk/A7800Hawk.ISettable.cs

@@ -18,17 +18,17 @@ namespace BizHawk.Emulation.Cores.Atari.A7800Hawk
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(A7800Settings o)
+		public PutSettingsDirtyBits PutSettings(A7800Settings o)
 		{
 			_settings = o;
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(A7800SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(A7800SyncSettings o)
 		{
 			bool ret = A7800SyncSettings.NeedsReboot(_syncSettings, o);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		private A7800Settings _settings = new A7800Settings();

BizHawk.Emulation.Cores/Consoles/Coleco/ColecoVision.ISettable.cs

@@ -18,18 +18,18 @@ namespace BizHawk.Emulation.Cores.ColecoVision
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(ColecoSettings o)
+		public PutSettingsDirtyBits PutSettings(ColecoSettings o)
 		{
 			_settings = o;
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(ColecoSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(ColecoSyncSettings o)
 		{
 			bool ret = o.SkipBiosIntro != _syncSettings.SkipBiosIntro;
 			ret |= ColecoSyncSettings.NeedsReboot(_syncSettings, o);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		public class ColecoSettings

BizHawk.Emulation.Cores/Consoles/Fairchild/ChannelF/ChannelF.ISettable.cs

@@ -19,17 +19,17 @@ namespace BizHawk.Emulation.Cores.Consoles.ChannelF
 			return SyncSettings.Clone();
 		}
 
-		public bool PutSettings(ChannelFSettings o)
+		public PutSettingsDirtyBits PutSettings(ChannelFSettings o)
 		{
 			Settings = o;
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(ChannelFSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(ChannelFSyncSettings o)
 		{
 			bool ret = ChannelFSyncSettings.NeedsReboot(SyncSettings, o);
 			SyncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		public class ChannelFSettings

BizHawk.Emulation.Cores/Consoles/GCE/Vectrex/VectrexHawk.ISettable.cs

@@ -19,17 +19,17 @@ namespace BizHawk.Emulation.Cores.Consoles.Vectrex
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(VectrexSettings o)
+		public PutSettingsDirtyBits PutSettings(VectrexSettings o)
 		{
 			_settings = o;
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(VectrexSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(VectrexSyncSettings o)
 		{
 			bool ret = VectrexSyncSettings.NeedsReboot(_syncSettings, o);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		private VectrexSettings _settings = new VectrexSettings();

BizHawk.Emulation.Cores/Consoles/Intellivision/Intellivision.ISettable.cs

@@ -18,17 +18,17 @@ namespace BizHawk.Emulation.Cores.Intellivision
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(IntvSettings o)
+		public PutSettingsDirtyBits PutSettings(IntvSettings o)
 		{
 			_settings = o;
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(IntvSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(IntvSyncSettings o)
 		{
 			bool ret = IntvSyncSettings.NeedsReboot(_syncSettings, o);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		private IntvSettings _settings = new IntvSettings();

BizHawk.Emulation.Cores/Consoles/Magnavox/Odyssey2/O2Hawk.ISettable.cs

@@ -16,17 +16,17 @@ namespace BizHawk.Emulation.Cores.Consoles.O2Hawk
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(O2Settings o)
+		public PutSettingsDirtyBits PutSettings(O2Settings o)
 		{
 			_settings = o;
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(O2SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(O2SyncSettings o)
 		{
 			bool ret = O2SyncSettings.NeedsReboot(_syncSettings, o);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		public O2Settings _settings = new O2Settings();

BizHawk.Emulation.Cores/Consoles/NEC/PCFX/Tst.cs

@@ -330,19 +330,19 @@ namespace BizHawk.Emulation.Cores.Consoles.NEC.PCFX
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(Settings o)
+		public PutSettingsDirtyBits PutSettings(Settings o)
 		{
 			var ret = Settings.NeedsReboot(_settings, o);
 			_settings = o;
 			SetLayerSettings();
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(SyncSettings o)
 		{
 			var ret = SyncSettings.NeedsReboot(_syncSettings, o);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		private void SetNativeSettingsBeforeInit()

BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.ISettable.cs

@@ -15,7 +15,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 			return _settings.Clone();
 		}
 
-		public bool PutSettings(Settings o)
+		public PutSettingsDirtyBits PutSettings(Settings o)
 		{
 			LibmGBA.Layers mask = 0;
 			if (o.DisplayBG0) mask |= LibmGBA.Layers.BG0;
@@ -51,7 +51,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 			LibmGBA.BizSetPalette(Core, palette);
 
 			_settings = o;
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
 		private Settings _settings;
@@ -139,11 +139,11 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSyncSettings(SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(SyncSettings o)
 		{
 			bool ret = SyncSettings.NeedsReboot(o, _syncSettings);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		private SyncSettings _syncSettings;

BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/VBANext.ISettings.cs

@@ -18,16 +18,16 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(object o)
+		public PutSettingsDirtyBits PutSettings(object o)
 		{
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(SyncSettings o)
 		{
 			bool ret = SyncSettings.NeedsReboot(o, _syncSettings);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		private SyncSettings _syncSettings;

BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/GBHawk.ISettable.cs

@@ -20,17 +20,17 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(GBSettings o)
+		public PutSettingsDirtyBits PutSettings(GBSettings o)
 		{
 			_settings = o;
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(GBSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(GBSyncSettings o)
 		{
 			bool ret = GBSyncSettings.NeedsReboot(_syncSettings, o);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		private GBSettings _settings = new GBSettings();

BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawkLink/GBHawkLink.ISettable.cs

@@ -14,17 +14,17 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawkLink
 
 		public GBLinkSyncSettings GetSyncSettings() => linkSyncSettings.Clone();
 
-		public bool PutSettings(GBLinkSettings o)
+		public PutSettingsDirtyBits PutSettings(GBLinkSettings o)
 		{
 			linkSettings = o;
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(GBLinkSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(GBLinkSyncSettings o)
 		{
 			bool ret = GBLinkSyncSettings.NeedsReboot(linkSyncSettings, o);
 			linkSyncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		private GBLinkSettings linkSettings = new GBLinkSettings();

BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawkLink3x/GBHawkLink3x.ISettable.cs

@@ -14,17 +14,17 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawkLink3x
 
 		public GBLink3xSyncSettings GetSyncSettings() => Link3xSyncSettings.Clone();
 
-		public bool PutSettings(GBLink3xSettings o)
+		public PutSettingsDirtyBits PutSettings(GBLink3xSettings o)
 		{
 			Link3xSettings = o;
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(GBLink3xSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(GBLink3xSyncSettings o)
 		{
 			bool ret = GBLink3xSyncSettings.NeedsReboot(Link3xSyncSettings, o);
 			Link3xSyncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		private GBLink3xSettings Link3xSettings = new GBLink3xSettings();

BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawkLink4x/GBHawkLink4x.ISettable.cs

@@ -14,17 +14,17 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawkLink4x
 
 		public GBLink4xSyncSettings GetSyncSettings() => Link4xSyncSettings.Clone();
 
-		public bool PutSettings(GBLink4xSettings o)
+		public PutSettingsDirtyBits PutSettings(GBLink4xSettings o)
 		{
 			Link4xSettings = o;
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(GBLink4xSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(GBLink4xSyncSettings o)
 		{
 			bool ret = GBLink4xSyncSettings.NeedsReboot(Link4xSyncSettings, o);
 			Link4xSyncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		private GBLink4xSettings Link4xSettings = new GBLink4xSettings();

BizHawk.Emulation.Cores/Consoles/Nintendo/Gameboy/Gambatte.ISettable.cs

@@ -14,7 +14,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.Gameboy
 			return _settings.Clone();
 		}
 
-		public bool PutSettings(GambatteSettings o)
+		public PutSettingsDirtyBits PutSettings(GambatteSettings o)
 		{
 			_settings = o;
 			if (IsCGBMode())
@@ -26,7 +26,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.Gameboy
 				ChangeDMGColors(_settings.GBPalette);
 			}
 
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
 		public GambatteSyncSettings GetSyncSettings()
@@ -34,11 +34,11 @@ namespace BizHawk.Emulation.Cores.Nintendo.Gameboy
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSyncSettings(GambatteSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(GambatteSyncSettings o)
 		{
 			bool ret = GambatteSyncSettings.NeedsReboot(_syncSettings, o);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		private GambatteSettings _settings;

BizHawk.Emulation.Cores/Consoles/Nintendo/Gameboy/GambatteLink.ISettable.cs

@@ -21,14 +21,14 @@ namespace BizHawk.Emulation.Cores.Nintendo.Gameboy
 			);
 		}
 
-		public bool PutSettings(GambatteLinkSettings o)
+		public PutSettingsDirtyBits PutSettings(GambatteLinkSettings o)
 		{
-			return L.PutSettings(o.L) || R.PutSettings(o.R);
+			return (PutSettingsDirtyBits)((int)L.PutSettings(o.L) | (int)R.PutSettings(o.R));
 		}
 
-		public bool PutSyncSettings(GambatteLinkSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(GambatteLinkSyncSettings o)
 		{
-			return L.PutSyncSettings(o.L) || R.PutSyncSettings(o.R);
+			return (PutSettingsDirtyBits)((int)L.PutSyncSettings(o.L) | (int)R.PutSyncSettings(o.R));
 		}
 
 		public class GambatteLinkSettings

BizHawk.Emulation.Cores/Consoles/Nintendo/Gameboy/Sameboy.cs

@@ -245,18 +245,18 @@ namespace BizHawk.Emulation.Cores.Consoles.Nintendo.Gameboy
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(Settings o)
+		public PutSettingsDirtyBits PutSettings(Settings o)
 		{
 			var ret = Settings.NeedsReboot(_settings, o);
 			_settings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(SyncSettings o)
 		{
 			var ret = SyncSettings.NeedsReboot(_syncSettings, o);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		#endregion

BizHawk.Emulation.Cores/Consoles/Nintendo/N64/N64.ISettable.cs

@@ -14,17 +14,17 @@ namespace BizHawk.Emulation.Cores.Nintendo.N64
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(N64Settings o)
+		public PutSettingsDirtyBits PutSettings(N64Settings o)
 		{
 			_settings = o;
-			return true;
+			return PutSettingsDirtyBits.RebootCore;
 		}
 
-		public bool PutSyncSettings(N64SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(N64SyncSettings o)
 		{
 			_syncSettings = o;
 			SetControllerButtons();
-			return true;
+			return PutSettingsDirtyBits.RebootCore;
 		}
 
 		private void SetControllerButtons()

BizHawk.Emulation.Cores/Consoles/Nintendo/NDS/MelonDS_Settable.cs

@@ -30,14 +30,14 @@ namespace BizHawk.Emulation.Cores.Consoles.Nintendo.NDS
 			return ret;
 		}
 
-		public bool PutSettings(MelonSettings o)
+		public PutSettingsDirtyBits PutSettings(MelonSettings o)
 		{
 			_settings = o ?? new MelonSettings();
 			SetScaleFactor(_settings.ScaleFactor);
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(MelonSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(MelonSyncSettings o)
 		{
 			if (o == null)
 			{
@@ -54,7 +54,7 @@ namespace BizHawk.Emulation.Cores.Consoles.Nintendo.NDS
 			SetTimeAtBoot(o.TimeAtBoot);
 
 			// At present, no sync settings can be modified without requiring a reboot.
-			return true;
+			return PutSettingsDirtyBits.RebootCore;
 		}
 
 		[DllImport(dllPath)]

BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.ISettable.cs

@@ -12,7 +12,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 
 		public NESSyncSettings GetSyncSettings() => SyncSettings.Clone();
 
-		public bool PutSettings(NESSettings o)
+		public PutSettingsDirtyBits PutSettings(NESSettings o)
 		{
 			Settings = o;
 			if (Settings.ClipLeftAndRight)
@@ -30,14 +30,14 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 
 			apu.m_vol = Settings.APU_vol;
 
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(NESSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(NESSyncSettings o)
 		{
 			bool ret = NESSyncSettings.NeedsReboot(SyncSettings, o);
 			SyncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		internal NESSettings Settings = new NESSettings();

BizHawk.Emulation.Cores/Consoles/Nintendo/QuickNES/QuickNES.ISettable.cs

@@ -21,21 +21,21 @@ namespace BizHawk.Emulation.Cores.Consoles.Nintendo.QuickNES
 			return _syncSettingsNext.Clone();
 		}
 
-		public bool PutSettings(QuickNESSettings o)
+		public PutSettingsDirtyBits PutSettings(QuickNESSettings o)
 		{
 			_settings = o;
 			QN.qn_set_sprite_limit(Context, _settings.NumSprites);
 			RecalculateCrops();
 			CalculatePalette();
 
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(QuickNESSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(QuickNESSyncSettings o)
 		{
 			bool ret = QuickNESSyncSettings.NeedsReboot(_syncSettings, o);
 			_syncSettingsNext = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		private QuickNESSettings _settings;

BizHawk.Emulation.Cores/Consoles/Nintendo/SNES/LibsnesCore.ISettable.cs

@@ -14,7 +14,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(SnesSettings o)
+		public PutSettingsDirtyBits PutSettings(SnesSettings o)
 		{
 			bool refreshNeeded = o.Palette != _settings.Palette;
 			_settings = o;
@@ -23,17 +23,17 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES
 				RefreshPalette();
 			}
 
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(SnesSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(SnesSyncSettings o)
 		{
 			bool ret = o.LeftPort != _syncSettings.LeftPort
 				|| o.RightPort != _syncSettings.RightPort
 				|| o.LimitAnalogChangeSensitivity != _syncSettings.LimitAnalogChangeSensitivity;
 
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		private SnesSettings _settings;

BizHawk.Emulation.Cores/Consoles/Nintendo/SNES9X/Snes9x.cs

@@ -308,7 +308,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES9X
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(Settings o)
+		public PutSettingsDirtyBits PutSettings(Settings o)
 		{
 			_settings = o;
 			int s = 0;
@@ -334,14 +334,14 @@ namespace BizHawk.Emulation.Cores.Nintendo.SNES9X
 			if (o.ShowSprites3) l |= 2048;
 			_core.biz_set_layers(l);
 
-			return false; // no reboot needed
+			return PutSettingsDirtyBits.None; // no reboot needed
 		}
 
-		public bool PutSyncSettings(SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(SyncSettings o)
 		{
 			var ret = SyncSettings.NeedsReboot(_syncSettings, o);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		public class Settings

BizHawk.Emulation.Cores/Consoles/Nintendo/SubGBHawk/SubGBHawk.cs

@@ -58,7 +58,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.SubGBHawk
 
 		public GBHawk.GBHawk.GBSettings GetSettings() => _GBCore.GetSettings();
 		public GBHawk.GBHawk.GBSyncSettings GetSyncSettings() => _GBCore.GetSyncSettings();
-		public bool PutSettings(GBHawk.GBHawk.GBSettings o) => _GBCore.PutSettings(o);
+		public PutSettingsDirtyBits PutSettings(GBHawk.GBHawk.GBSettings o) => _GBCore.PutSettings(o);
-		public bool PutSyncSettings(GBHawk.GBHawk.GBSyncSettings o) => _GBCore.PutSyncSettings(o);
+		public PutSettingsDirtyBits PutSyncSettings(GBHawk.GBHawk.GBSyncSettings o) => _GBCore.PutSyncSettings(o);
 	}
 }

BizHawk.Emulation.Cores/Consoles/Nintendo/SubNESHawk/SubNESHawk.cs

@@ -84,7 +84,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.SubNESHawk
 
 		public NES.NES.NESSettings GetSettings() => _nesCore.GetSettings();
 		public NES.NES.NESSyncSettings GetSyncSettings() => _nesCore.GetSyncSettings();
-		public bool PutSettings(NES.NES.NESSettings o) => _nesCore.PutSettings(o);
+		public PutSettingsDirtyBits PutSettings(NES.NES.NESSettings o) => _nesCore.PutSettings(o);
-		public bool PutSyncSettings(NES.NES.NESSyncSettings o) => _nesCore.PutSyncSettings(o);
+		public PutSettingsDirtyBits PutSyncSettings(NES.NES.NESSyncSettings o) => _nesCore.PutSyncSettings(o);
 	}
 }

BizHawk.Emulation.Cores/Consoles/Nintendo/VB/VirtualBoyee.cs

@@ -234,18 +234,18 @@ namespace BizHawk.Emulation.Cores.Consoles.Nintendo.VB
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(Settings o)
+		public PutSettingsDirtyBits PutSettings(Settings o)
 		{
 			var ret = Settings.NeedsReboot(_settings, o);
 			_settings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(SyncSettings o)
 		{
 			var ret = SyncSettings.NeedsReboot(_syncSettings, o);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		#endregion

BizHawk.Emulation.Cores/Consoles/PC Engine/PCEngine.ISettable.cs

@@ -17,7 +17,7 @@ namespace BizHawk.Emulation.Cores.PCEngine
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(PCESettings o)
+		public PutSettingsDirtyBits PutSettings(PCESettings o)
 		{
 			bool ret;
 			if (o.ArcadeCardRewindHack != Settings.ArcadeCardRewindHack
@@ -32,14 +32,14 @@ namespace BizHawk.Emulation.Cores.PCEngine
 
 			Settings = o;
 
-			return ret;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(PCESyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(PCESyncSettings o)
 		{
 			bool ret = PCESyncSettings.NeedsReboot(o, _syncSettings);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		public PCESettings Settings;

BizHawk.Emulation.Cores/Consoles/SNK/NeoGeoPort.cs

@@ -166,16 +166,16 @@ namespace BizHawk.Emulation.Cores.Consoles.SNK
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(object o)
+		public PutSettingsDirtyBits PutSettings(object o)
 		{
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(SyncSettings o)
 		{
 			var ret = SyncSettings.NeedsReboot(_syncSettings, o);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		#endregion

BizHawk.Emulation.Cores/Consoles/Sega/GGHawkLink/GGHawkLink.ISettable.cs

@@ -16,17 +16,17 @@ namespace BizHawk.Emulation.Cores.Sega.GGHawkLink
 			return linkSyncSettings.Clone();
 		}
 
-		public bool PutSettings(GGLinkSettings o)
+		public PutSettingsDirtyBits PutSettings(GGLinkSettings o)
 		{
 			linkSettings = o;
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(GGLinkSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(GGLinkSyncSettings o)
 		{
 			bool ret = GGLinkSyncSettings.NeedsReboot(linkSyncSettings, o);
 			linkSyncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		private GGLinkSettings linkSettings = new GGLinkSettings();

BizHawk.Emulation.Cores/Consoles/Sega/PicoDrive/PicoDrive.cs

@@ -229,16 +229,16 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.PicoDrive
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(object o)
+		public PutSettingsDirtyBits PutSettings(object o)
 		{
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(SyncSettings o)
 		{
 			var ret = SyncSettings.NeedsReboot(_syncSettings, o);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		#endregion

BizHawk.Emulation.Cores/Consoles/Sega/SMS/SMS.ISettable.cs

@@ -9,18 +9,18 @@ namespace BizHawk.Emulation.Cores.Sega.MasterSystem
 
 		public SmsSyncSettings GetSyncSettings() => SyncSettings.Clone();
 
-		public bool PutSettings(SmsSettings o)
+		public PutSettingsDirtyBits PutSettings(SmsSettings o)
 		{
 			bool ret = SmsSettings.RebootNeeded(Settings, o);
 			Settings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(SmsSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(SmsSyncSettings o)
 		{
 			bool ret = SmsSyncSettings.RebootNeeded(SyncSettings, o);
 			SyncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		internal SmsSettings Settings { get; private set; }

BizHawk.Emulation.Cores/Consoles/Sega/Saturn/Saturnus.cs

@@ -439,7 +439,7 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.Saturn
 			return _settings.Clone();
 		}
 
-		public bool PutSettings(Settings s)
+		public PutSettingsDirtyBits PutSettings(Settings s)
 		{
 			var ret = Settings.NeedsReboot(_settings, s);
 			_settings = s;
@@ -449,7 +449,7 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.Saturn
 			//(the correct aspect ratio is no longer an option for other reasons)
 			//_core.SetVideoParameters(s.CorrectAspectRatio, s.HBlend, s.HOverscan, sls, sle);
 
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		public SyncSettings GetSyncSettings()
@@ -457,11 +457,11 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.Saturn
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSyncSettings(SyncSettings s)
+		public PutSettingsDirtyBits PutSyncSettings(SyncSettings s)
 		{
 			var ret = SyncSettings.NeedsReboot(_syncSettings, s);
 			_syncSettings = s;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		private void SetVideoParameters()

BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/GPGX.ISettable.cs

@@ -21,19 +21,19 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.gpgx
 			return _syncSettings.Clone();
 		}
 
-		public bool PutSettings(GPGXSettings o)
+		public PutSettingsDirtyBits PutSettings(GPGXSettings o)
 		{
 			bool ret = GPGXSettings.NeedsReboot(_settings, o);
 			_settings = o;
 			Core.gpgx_set_draw_mask(_settings.GetDrawMask());
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(GPGXSyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(GPGXSyncSettings o)
 		{
 			bool ret = GPGXSyncSettings.NeedsReboot(_syncSettings, o);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		private class UintToHexConverter : TypeConverter

BizHawk.Emulation.Cores/Consoles/Sony/PSX/Octoshock.cs

@@ -1271,17 +1271,17 @@ namespace BizHawk.Emulation.Cores.Sony.PSX
 			return _SyncSettings.Clone();
 		}
 
-		public bool PutSettings(Settings o)
+		public PutSettingsDirtyBits PutSettings(Settings o)
 		{
 			_Settings.Validate();
 			_Settings = o;
 
 			//TODO - store settings into core? or we can just keep doing it before frameadvance
 
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(SyncSettings o)
 		{
 			//currently LEC and pad settings changes both require reboot
 			bool reboot = true;
@@ -1293,7 +1293,7 @@ namespace BizHawk.Emulation.Cores.Sony.PSX
 			_SyncSettings = o;
 
 
-			return reboot;
+			return reboot ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		#endregion

BizHawk.Emulation.Cores/Consoles/WonderSwan/WonderSwan.ISettable.cs

@@ -158,19 +158,19 @@ namespace BizHawk.Emulation.Cores.WonderSwan
 
 		public SyncSettings GetSyncSettings() => _syncSettings.Clone();
 
-		public bool PutSettings(Settings o)
+		public PutSettingsDirtyBits PutSettings(Settings o)
 		{
 			_settings = o;
 			var native = _settings.GetNativeSettings();
 			BizSwan.bizswan_putsettings(Core, ref native);
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(SyncSettings o)
 		{
 			bool ret = SyncSettings.NeedsReboot(o, _syncSettings);
 			_syncSettings = o;
-			return ret;
+			return ret ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 	}

BizHawk.Emulation.Cores/Libretro/LibretroCoreSettings.cs

@@ -1,5 +1,6 @@
 using Newtonsoft.Json;
 using BizHawk.Common;
+using BizHawk.Emulation.Common;
 
 namespace BizHawk.Emulation.Cores.Libretro
 {
@@ -49,17 +50,17 @@ namespace BizHawk.Emulation.Cores.Libretro
 			return _SyncSettings.Clone();
 		}
 
-		public bool PutSettings(Settings o)
+		public PutSettingsDirtyBits PutSettings(Settings o)
 		{
 			_Settings.Validate();
 			_Settings = o;
 
 			//TODO - store settings into core? or we can just keep doing it before frameadvance
 
-			return false;
+			return PutSettingsDirtyBits.None;
 		}
 
-		public bool PutSyncSettings(SyncSettings o)
+		public PutSettingsDirtyBits PutSyncSettings(SyncSettings o)
 		{
 			bool reboot = false;
 
@@ -68,7 +69,7 @@ namespace BizHawk.Emulation.Cores.Libretro
 
 			_SyncSettings = o;
 
-			return reboot;
+			return reboot ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 	}