diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/FDS/FDS.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/FDS/FDS.cs
index a37c230a4b..c66a58d0b6 100644
--- a/BizHawk.Emulation/Consoles/Nintendo/NES/FDS/FDS.cs
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/FDS/FDS.cs
@@ -15,15 +15,73 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 	[NES.INESBoardImplCancel]
 	public class FDS : NES.NESBoardBase
 	{
-		/// <summary>
-		/// fds bios image; should be 8192 bytes
-		/// </summary>
+		#region configuration
+		/// <summary>FDS bios image; should be 8192 bytes</summary>
 		public byte[] biosrom;
-
-		/// <summary>
-		/// .fds disk image
-		/// </summary>
+		/// <summary>.FDS disk image</summary>
 		byte[] diskimage;
+		#endregion
+
+		#region state
+		RamAdapter diskdrive;
+		FDSAudio audio;
+		/// <summary>0-2, how many ppu cycles since audio was last triggered</summary>
+		int audioclock;
+		/// <summary>currently loaded side of the .FDS image, 0 based</summary>
+		int? currentside = null;
+		/// <summary>collection of diffs (as provided by the RamAdapter) for each side in the .FDS image</summary>
+		byte[][] diskdiffs;
+
+		bool _diskirq;
+		bool _timerirq;
+
+		/// <summary>disk io ports enabled; see 4023.0</summary>
+		bool diskenable = false;
+		/// <summary>sound io ports enabled; see 4023.1</summary>
+		bool soundenable = false;
+		/// <summary>read on 4033, write on 4026</summary>
+		byte reg4026;
+
+		/// <summary>timer reload</summary>
+		int timerlatch;
+		/// <summary>timer current value</summary>
+		int timervalue;
+		/// <summary>4022.0,1</summary>
+		byte timerreg;
+		#endregion
+
+		public override void SyncState(Serializer ser)
+		{
+			base.SyncState(ser);
+			ser.BeginSection("FDS");
+			ser.BeginSection("RamAdapter");
+			diskdrive.SyncState(ser);
+			ser.EndSection();
+			ser.BeginSection("audio");
+			audio.SyncState(ser);
+			ser.EndSection();
+			ser.Sync("audioclock", ref audioclock);			
+			{
+				// silly little hack
+				int tmp = currentside != null ? (int)currentside : 1234567;
+				ser.Sync("currentside", ref tmp);
+				currentside = tmp == 1234567 ? null : (int?)tmp;
+			}
+			for (int i = 0; i < NumSides; i++)
+				ser.Sync("diskdiffs" + i, ref diskdiffs[i], false);
+			ser.Sync("_timerirq", ref _timerirq);
+			ser.Sync("_diskirq", ref _diskirq);
+			ser.Sync("diskenable", ref diskenable);
+			ser.Sync("soundenable", ref soundenable);
+			ser.Sync("reg4026", ref reg4026);
+			ser.Sync("timerlatch", ref timerlatch);
+			ser.Sync("timervalue", ref timervalue);
+			ser.Sync("timerreg", ref timerreg);
+			ser.EndSection();
+
+			SetIRQ();
+		}
+
 
 		/// <summary>
 		/// should only be called once, before emulation begins
@@ -35,11 +93,6 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 			diskdiffs = new byte[NumSides][];
 		}
 
-
-		RamAdapter diskdrive;
-		FDSAudio audio;
-		int audioclock;
-
 		// as we have [INESBoardImplCancel], this will only be called with an fds disk image
 		public override bool Configure(NES.EDetectionOrigin origin)
 		{
@@ -56,21 +109,13 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 			audio = new FDSAudio();
 
 			InsertSide(0);
-
-			// set mirroring
-
+			// set mirroring??
 			return true;
 		}
 
 		// with a bit of change, these methods could work with a better disk format
 
-		public int NumSides
-		{
-			get
-			{
-				return diskimage[4];
-			}
-		}
+		public int NumSides { get { return diskimage[4]; } }
 
 		public void Eject()
 		{
@@ -84,6 +129,8 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 
 		public void InsertSide(int side)
 		{
+			if (side >= NumSides)
+				throw new ArgumentOutOfRangeException();
 			byte[] buf = new byte[65500];
 			Buffer.BlockCopy(diskimage, 16 + side * 65500, buf, 0, 65500);
 			diskdrive.InsertBrokenImage(buf, false /*true*/);
@@ -92,10 +139,6 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 			currentside = side;
 		}
 
-		int? currentside = null;
-
-		byte[][] diskdiffs;
-
 		public byte[] ReadSaveRam()
 		{
 			// update diff for currently loaded disk first!
@@ -169,20 +212,12 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 		{
 			IRQSignal = _diskirq || _timerirq;
 		}
-		bool _diskirq;
-		bool _timerirq;
 		bool diskirq { get { return _diskirq; } set { _diskirq = value; SetIRQ(); } }
 		bool timerirq { get { return _timerirq; } set { _timerirq = value; SetIRQ(); } }
 
-		bool diskenable = false;
-		bool soundenable = false;
 
 		
-		int timerlatch;
-		int timervalue;
-		byte timerreg;
 
-		byte reg4026;
 
 		public override void WriteEXP(int addr, byte value)
 		{
@@ -268,7 +303,8 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 					if (diskenable)
 					{
 						ret = reg4026;
-						ret &= 0x80; // set battery flag
+						// uncomment to set low battery flag
+						// ret &= 0x7f;
 					}
 					break;
 			}
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/FDS/FDSAudio.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/FDS/FDSAudio.cs
index f823bd25d2..2ca361c585 100644
--- a/BizHawk.Emulation/Consoles/Nintendo/NES/FDS/FDSAudio.cs
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/FDS/FDSAudio.cs
@@ -8,6 +8,53 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 	// http://wiki.nesdev.com/w/index.php/FDS_audio
 	public class FDSAudio
 	{
+		public void SyncState(Serializer ser)
+		{
+			// no need to sync the DCFilter or the samplebuff
+			ser.Sync("waveram", ref waveram, false);
+			ser.Sync("waverampos", ref waverampos);
+
+			ser.Sync("volumespd", ref volumespd);
+			ser.Sync("r4080_6", ref r4080_6);
+			ser.Sync("r4080_7", ref r4080_7);
+
+			ser.Sync("frequency", ref frequency);
+			ser.Sync("r4083_6", ref r4083_6);
+			ser.Sync("r4083_7", ref r4083_7);
+
+			ser.Sync("sweepspd", ref sweepspd);
+			ser.Sync("r4084_6", ref r4084_6);
+			ser.Sync("r4084_7", ref r4084_7);
+
+			ser.Sync("sweepbias", ref sweepbias);
+
+			ser.Sync("modfreq", ref modfreq);
+			ser.Sync("r4087_7", ref r4087_7);
+
+			ser.Sync("modtable", ref modtable, false);
+			ser.Sync("modtablepos", ref modtablepos);
+
+			ser.Sync("mastervol_num", ref mastervol_num);
+			ser.Sync("mastervol_den", ref mastervol_den);
+			ser.Sync("waveram_writeenable", ref waveram_writeenable);
+
+			ser.Sync("envspeed", ref envspeed);
+
+			ser.Sync("volumeclock", ref volumeclock);
+			ser.Sync("sweepclock", ref sweepclock);
+			ser.Sync("modclock", ref modclock);
+			ser.Sync("mainclock", ref mainclock);
+
+			ser.Sync("modoutput", ref modoutput);
+
+			ser.Sync("volumegain", ref volumegain);
+			ser.Sync("sweepgain", ref sweepgain);
+
+			ser.Sync("waveramoutput", ref waveramoutput);
+
+			ser.Sync("latchedoutput", ref latchedoutput);
+		}
+
 		//4040:407f
 		byte[] waveram = new byte[64];
 		int waverampos;
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/FDS/RamAdapter.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/FDS/RamAdapter.cs
index 4f423b1723..83d0296df6 100644
--- a/BizHawk.Emulation/Consoles/Nintendo/NES/FDS/RamAdapter.cs
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/FDS/RamAdapter.cs
@@ -11,6 +11,8 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 	/// </summary>
 	public class RamAdapter
 	{
+		#region fix broken images
+
 		static void WriteBlock(Stream dest, byte[] data, int pregap)
 		{
 			for (int i = 0; i < pregap - 1; i++)
@@ -87,6 +89,10 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 			return tmp;
 		}
 
+		#endregion
+
+		#region crc
+
 		/// <summary>
 		/// advance a 16 bit CRC register with 1 new input bit.  x.25 standard
 		/// </summary>
@@ -118,6 +124,41 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 			return crc;
 		}
 
+		#endregion
+
+		public void SyncState(Serializer ser)
+		{
+			ser.Sync("originaldisk", ref originaldisk, false);
+			ser.Sync("disk", ref disk, false);
+			ser.Sync("diskpos", ref diskpos);
+			ser.Sync("disksize", ref disksize);
+			ser.Sync("writeprotect", ref writeprotect);
+
+			ser.Sync("cycleswaiting", ref cycleswaiting);
+			{
+				int tmp = (int)state;
+				ser.Sync("state", ref tmp);
+				state = (RamAdapterState)tmp;
+			}
+			ser.Sync("cached4025", ref cached4025);
+			ser.Sync("irq", ref irq);
+			ser.Sync("transferreset", ref transferreset);
+
+			ser.Sync("crc", ref crc);
+			ser.Sync("writecomputecrc", ref writecomputecrc);
+
+			ser.Sync("readreg", ref readreg);
+			ser.Sync("writereg", ref writereg);
+			ser.Sync("readregpos", ref readregpos);
+			ser.Sync("writeregpos", ref writeregpos);
+			ser.Sync("readreglatch", ref readreglatch);
+			ser.Sync("writereglatch", ref writereglatch);
+
+			ser.Sync("bytetransferflag", ref bytetransferflag);
+			ser.Sync("lookingforendofgap", ref lookingforendofgap);
+		}
+
+		#region state
 		/// <summary>the original contents of this disk when it was loaded.  for virtual saveram diff</summary>
 		byte[] originaldisk = null;
 		/// <summary>currently loaded disk side (ca 65k bytes)</summary>
@@ -129,6 +170,38 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 		/// <summary>true if current disk is writeprotected</summary>
 		bool writeprotect = true;
 
+		/// <summary>ppu cycles until next action</summary>
+		int cycleswaiting = 0;
+		/// <summary>physical state of the drive</summary>
+		RamAdapterState state = RamAdapterState.IDLE;
+
+		/// <summary>cached 4025 write; can be modified internally by some things</summary>
+		byte cached4025;
+		/// <summary>can be raised on byte transfer complete</summary>
+		public bool irq;
+		/// <summary>true if 4025.1 is set to true</summary>
+		bool transferreset = false;
+
+		/// <summary>
+		/// 16 bit CRC register.  in normal operation, will become all 0 on finishing a read (see x.25 spec for more details)
+		/// </summary>
+		ushort crc = 0;
+		/// <summary>true if data being written to disk is currently being computed in CRC</summary>
+		bool writecomputecrc; // this has to be latched because the "flush CRC" call comes in the middle of a byte, of course
+
+		// read and write shift regs, with bit positions and latched values for reload
+		byte readreg;
+		byte writereg;
+		int readregpos;
+		int writeregpos;
+		byte readreglatch;
+		byte writereglatch;
+
+		bool bytetransferflag;
+		bool lookingforendofgap = false;
+
+		#endregion
+
 		/// <summary>
 		/// eject the loaded disk
 		/// </summary>
@@ -221,11 +294,6 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 		}
 
 		// all timings are in terms of PPU cycles (@5.37mhz)
-		/// <summary>
-		/// ppu cycles until next action
-		/// </summary>
-		int cycleswaiting = 0;
-
 		enum RamAdapterState
 		{
 			/// <summary>moving over the disk</summary>
@@ -239,10 +307,6 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 			/// <summary>nothing happening</summary>
 			IDLE,
 		};
-		/// <summary>
-		/// physical state of the drive
-		/// </summary>
-		RamAdapterState state = RamAdapterState.IDLE;
 
 		/// <summary>
 		/// set cycleswaiting param after a state change
@@ -285,23 +349,6 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 			//Console.WriteLine("!!4024:{0:x2}", value);
 		}
 
-		/// <summary>
-		/// cached 4025 write; can be modified internally by some things
-		/// </summary>
-		byte cached4025;
-
-		/// <summary>
-		/// can be raised on byte transfer complete
-		/// </summary>
-		public bool irq;
-
-		/// <summary>true if 4025.1 is set to true</summary>
-		bool transferreset = false;
-
-		/// <summary>
-		/// 16 bit CRC register.  in normal operation, will become all 0 on finishing a read (see x.25 spec for more details)
-		/// </summary>
-		ushort crc = 0;
 
 		/// <summary>
 		/// control reg
@@ -374,11 +421,6 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 			return ret;
 		}
 
-		/// <summary>
-		/// DEBUG ONLY
-		/// </summary>
-		int lastreaddiskpos;
-
 		/// <summary>
 		/// more status stuff
 		/// </summary>
@@ -463,22 +505,6 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 			}
 		}
 
-		// read and write shift regs, with bit positions and latched values for reload
-		byte readreg;
-		byte writereg;
-		int readregpos;
-		int writeregpos;
-		byte readreglatch;
-		byte writereglatch;
-	
-		bool bytetransferflag;
-
-		bool lookingforendofgap = false;
-
-		/// <summary>
-		/// true if data being written to disk is currently being computed in CRC
-		/// </summary>
-		bool writecomputecrc; // this has to be latched because the "flush CRC" call comes in the middle of a byte, of course
 
 		void Read()
 		{
@@ -516,7 +542,7 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 					bytetransferflag = true;
 					if ((cached4025 & 0x80) != 0)
 						irq = true;
-					lastreaddiskpos = diskpos;
+					//lastreaddiskpos = diskpos;
 					//Console.WriteLine("{0:x2} {1} @{2}", readreg, (cached4025 & 0x80) != 0 ? "RAISE" : "    ", diskpos);
 					readreglatch = readreg;