diff --git a/src/drivers/libretro/fceu/fceu-endian.c b/src/drivers/libretro/fceu/fceu-endian.c
index feb5e1f..cb52ec3 100644
--- a/src/drivers/libretro/fceu/fceu-endian.c
+++ b/src/drivers/libretro/fceu/fceu-endian.c
@@ -77,6 +77,29 @@ int read32le(uint32 *Bufo, FILE *fp)
    return 1;
 }
 
+int write32le_mem(uint32 b, memstream_t *mem)
+{
+   uint8 s[4];
+   s[0]=b;
+   s[1]=b>>8;
+   s[2]=b>>16;
+   s[3]=b>>24;
+   return((memstream_write(mem, s, 4)<4)?0:4);
+}
+
+int read32le_mem(uint32 *Bufo, memstream_t *mem)
+{
+   uint32 buf;
+   if(memstream_read(mem, &buf, 4)<4)
+      return 0;
+#ifdef LSB_FIRST
+   *(uint32*)Bufo=buf;
+#else
+   *(uint32*)Bufo=((buf&0xFF)<<24)|((buf&0xFF00)<<8)|((buf&0xFF0000)>>8)|((buf&0xFF000000)>>24);
+#endif
+   return 1;
+}
+
 int read16le(char *d, FILE *fp)
 {
 #ifdef LSB_FIRST
diff --git a/src/drivers/libretro/fceu/fceu-endian.h b/src/drivers/libretro/fceu/fceu-endian.h
index 00d2a3d..333e679 100644
--- a/src/drivers/libretro/fceu/fceu-endian.h
+++ b/src/drivers/libretro/fceu/fceu-endian.h
@@ -2,6 +2,10 @@
 #define _FCEU_ENDIAN_H
 
 #include "fceu-memory.h"
+#include "memstream.h"
+
+int write32le_mem(uint32 b, memstream_t *mem);
+int read32le_mem(uint32 *Bufo, memstream_t *mem);
 
 int write16le(uint16 b, FILE *fp);
 int write32le(uint32 b, FILE *fp);
diff --git a/src/drivers/libretro/fceu/state.c b/src/drivers/libretro/fceu/state.c
index 805c177..057af7a 100644
--- a/src/drivers/libretro/fceu/state.c
+++ b/src/drivers/libretro/fceu/state.c
@@ -81,6 +81,49 @@ SFORMAT SFCPUC[] = {
 	{ 0 }
 };
 
+static int SubWrite_Mem(memstream_t *mem, SFORMAT *sf)
+{
+   uint32 acc=0;
+
+   while(sf->v)
+   {
+      if(sf->s==~0) /* Link to another struct. */
+      {
+         uint32 tmp;
+
+         if(!(tmp=SubWrite_Mem(mem, (SFORMAT *)sf->v)))
+            return(0);
+         acc+=tmp;
+         sf++;
+         continue;
+      }
+
+      acc+=8; /* Description + size */
+      acc+=sf->s&(~RLSB);
+
+      if(mem) /* Are we writing or calculating the size of this block? */
+      {
+         memstream_write(mem, sf->desc, 4);
+         write32le_mem(sf->s&(~RLSB), mem);
+
+#ifndef LSB_FIRST
+         if(sf->s&RLSB)
+            FlipByteOrder(sf->v,sf->s&(~RLSB));
+#endif
+
+         memstream_write(mem, (uint8 *)sf->v, sf->s&(~RLSB));
+         /* Now restore the original byte order. */
+#ifndef LSB_FIRST
+         if(sf->s&RLSB)
+            FlipByteOrder(sf->v,sf->s&(~RLSB));
+#endif
+      }
+      sf++;
+   }
+
+   return acc;
+}
+
 static int SubWrite(MEM_TYPE *st, SFORMAT *sf) {
 	uint32 acc = 0;
 
@@ -134,6 +177,20 @@ static int WriteStateChunk(MEM_TYPE *st, int type, SFORMAT *sf)
    return(bsize + 5);
 }
 
+static int WriteStateChunk_Mem(memstream_t *mem, int type, SFORMAT *sf)
+{
+   int bsize;
+
+   memstream_putc(mem, type);
+
+   bsize = SubWrite(0,sf);
+   write32le_mem(bsize, mem);
+
+   if (!SubWrite_Mem(mem, sf))
+      return 0;
+   return bsize + 5;
+}
+
 static SFORMAT *CheckS(SFORMAT *sf, uint32 tsize, char *desc)
 {
    while (sf->v)
@@ -157,6 +214,36 @@ static SFORMAT *CheckS(SFORMAT *sf, uint32 tsize, char *desc)
    return(0);
 }
 
+static int ReadStateChunk_Mem(memstream_t *mem, SFORMAT *sf, int size)
+{
+   SFORMAT *tmp;
+   int temp;
+   temp=memstream_pos(mem);
+
+   while(memstream_pos(mem)<temp+size)
+   {
+      uint32 tsize;
+      char toa[4];
+      if(memstream_read(mem, toa, 4)<=0)
+         return 0;
+
+      read32le_mem(&tsize,mem);
+
+      if((tmp=CheckS(sf,tsize,toa)))
+      {
+         memstream_read(mem, (uint8 *)tmp->v, tmp->s&(~RLSB));
+
+#ifndef LSB_FIRST
+         if(tmp->s&RLSB)
+            FlipByteOrder(tmp->v,tmp->s&(~RLSB));
+#endif
+      }
+      else
+         memstream_seek(mem,tsize,SEEK_CUR);
+   }
+   return 1;
+}
+
 static int ReadStateChunk(MEM_TYPE *st, SFORMAT *sf, int size)
 {
 	SFORMAT *tmp;
@@ -186,6 +273,59 @@ static int ReadStateChunk(MEM_TYPE *st, SFORMAT *sf, int size)
 	return 1;
 }
 
+static int ReadStateChunks_Mem(memstream_t *st, int32 totalsize)
+{
+   int t;
+   uint32 size;
+   int ret = 1;
+
+   while (totalsize > 0)
+   {
+      t = memstream_getc(st);
+      if (t == EOF)
+         break;
+      if (!read32le_mem(&size,st))
+         break;
+      totalsize -= size + 5;
+
+      switch(t)
+      {
+         case 1:
+            if (!ReadStateChunk_Mem(st, SFCPU, size))
+               ret = 0;
+            break;
+         case 2:
+            if (!ReadStateChunk_Mem(st, SFCPUC, size))
+               ret = 0;
+            else
+               X.mooPI = X.P; // Quick and dirty hack.
+            break;
+         case 3:
+            if (!ReadStateChunk_Mem(st, FCEUPPU_STATEINFO, size))
+               ret = 0;
+            break;
+         case 4:
+            if (!ReadStateChunk_Mem(st, FCEUCTRL_STATEINFO, size))
+               ret = 0;
+            break;
+         case 5:
+            if (!ReadStateChunk_Mem(st, FCEUSND_STATEINFO, size))
+               ret = 0;
+            break;
+         case 0x10:
+            if (!ReadStateChunk_Mem(st, SFMDATA, size))
+               ret = 0;
+            break;
+         default:
+            if (memstream_seek(st, size, SEEK_CUR) < 0)
+               goto endo;
+            break;
+      }
+   }
+endo:
+   return ret;
+}
+
 static int ReadStateChunks(MEM_TYPE *st, int32 totalsize)
 {
    int t;
@@ -274,6 +414,39 @@ int FCEUSS_SaveFP(MEM_TYPE *st)
 	return(1);
 }
 
+void FCEUSS_Save_Mem(void)
+{
+   memstream_t *mem = memstream_open(1);
+
+   static uint32 totalsize;
+   static uint8 header[16] = "FCS";
+
+   memset(header + 4, 0, 12);
+   header[3] = 0xFF;
+   FCEU_en32lsb(header + 8, FCEU_VERSION_NUMERIC);
+   memstream_write(mem, header, 16);
+
+   FCEUPPU_SaveState();
+   totalsize = WriteStateChunk_Mem(mem, 1, SFCPU);
+   totalsize += WriteStateChunk_Mem(mem, 2, SFCPUC);
+   totalsize += WriteStateChunk_Mem(mem, 3, FCEUPPU_STATEINFO);
+   totalsize += WriteStateChunk_Mem(mem, 4, FCEUCTRL_STATEINFO);
+   totalsize += WriteStateChunk_Mem(mem, 5, FCEUSND_STATEINFO);
+
+   if (SPreSave)
+      SPreSave();
+
+   totalsize += WriteStateChunk_Mem(mem, 0x10, SFMDATA);
+
+   if (SPreSave)
+      SPostSave();
+
+   memstream_seek(mem, 4, SEEK_SET);
+   write32le_mem(totalsize, mem);
+
+   memstream_close(mem);
+}
+
 void FCEUSS_Save(char *fname)
 {
 	MEM_TYPE *st = NULL;
@@ -322,6 +495,40 @@ int FCEUSS_LoadFP(MEM_TYPE *st)
    return(x);
 }
 
+void FCEUSS_Load_Mem(void)
+{
+   memstream_t *mem = memstream_open(0);
+
+   uint8 header[16];
+   int stateversion;
+
+   memstream_read(mem, header, 16);
+
+   if (memcmp(header,"FCS",3) != 0)
+      return;
+
+   if (header[3] == 0xFF)
+      stateversion = FCEU_de32lsb(header + 8);
+   else
+      stateversion = header[3] * 100;
+
+   int x = ReadStateChunks_Mem(mem, *(uint32*)(header + 4));
+
+   if (stateversion < 9500)
+      X.IRQlow=0;
+
+   if (GameStateRestore)
+      GameStateRestore(stateversion);
+
+   if (x)
+   {
+      FCEUPPU_LoadState(stateversion);
+      FCEUSND_LoadState(stateversion);
+   }
+
+   memstream_close(mem);
+}
+
 int FCEUSS_Load(char *fname)
 {
 	MEM_TYPE *st;
diff --git a/src/drivers/libretro/libretro.c b/src/drivers/libretro/libretro.c
index 2b65a2e..100cabc 100644
--- a/src/drivers/libretro/libretro.c
+++ b/src/drivers/libretro/libretro.c
@@ -768,7 +768,7 @@ size_t retro_serialize_size(void)
       uint8_t *buffer = (uint8_t*)malloc(1000000);
       memstream_set_buffer(buffer, 1000000);
 
-      FCEUSS_Save("");
+      FCEUSS_Save_Mem();
       serialize_size = memstream_get_last_size();
       free(buffer);
    }
@@ -782,7 +782,7 @@ bool retro_serialize(void *data, size_t size)
       return false;
 
    memstream_set_buffer((uint8_t*)data, size);
-   FCEUSS_Save("");
+   FCEUSS_Save_Mem();
    return true;
 }
 
@@ -792,7 +792,7 @@ bool retro_unserialize(const void * data, size_t size)
       return false;
 
    memstream_set_buffer((uint8_t*)data, size);
-   FCEUSS_Load("");
+   FCEUSS_Load_Mem();
    return true;
 }
 
diff --git a/src/state.h b/src/state.h
index 5d9182d..c32c7ef 100644
--- a/src/state.h
+++ b/src/state.h
@@ -28,6 +28,9 @@ int FCEUSS_Load(char *);
 int FCEUSS_SaveFP(MEM_TYPE *);
 int FCEUSS_LoadFP(MEM_TYPE *);
 
+void FCEUSS_Load_Mem(void);
+void FCEUSS_Save_Mem(void);
+
 extern int CurrentState;
 void FCEUSS_CheckStates(void);