diff --git a/src/emucore/Cart3E.cxx b/src/emucore/Cart3E.cxx
index 90ef00731..ec9c52df1 100644
--- a/src/emucore/Cart3E.cxx
+++ b/src/emucore/Cart3E.cxx
@@ -232,7 +232,9 @@ int Cartridge3E::bank()
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 int Cartridge3E::bankCount()
 {
-  return mySize >> 11;
+  // In addition to the number of 2K banks in ROM, there are 32 more 1K
+  // banks for RAM (doubled to 2K because of a read and write port)
+  return (mySize >> 11) + 32;
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
diff --git a/src/emucore/Cart3E.hxx b/src/emucore/Cart3E.hxx
index a8d052857..5e50e307e 100644
--- a/src/emucore/Cart3E.hxx
+++ b/src/emucore/Cart3E.hxx
@@ -172,7 +172,7 @@ class Cartridge3E : public Cartridge
     uInt8* myImage;
 
     // RAM contents. For now every ROM gets all 32K of potential RAM
-    uInt8 myRam[32768];
+    uInt8 myRam[32 * 1024];
 
     // Size of the ROM image
     uInt32 mySize;
diff --git a/src/emucore/Cart4A50.cxx b/src/emucore/Cart4A50.cxx
index 291110cd1..583ed47de 100644
--- a/src/emucore/Cart4A50.cxx
+++ b/src/emucore/Cart4A50.cxx
@@ -326,15 +326,40 @@ int Cartridge4A50::bank()
 int Cartridge4A50::bankCount()
 {
   // Doesn't support bankswitching in the normal sense
+  // There is one 'virtual' bank that can change in many different ways
   return 1;
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 bool Cartridge4A50::patch(uInt16 address, uInt8 value)
 {
-  // Doesn't support bankswitching in the normal sense
-  // TODO - add support for debugger
-  return false;
+  if((address & 0x1800) == 0x1000)           // 2K region from 0x1000 - 0x17ff
+  {
+    if(myIsRomLow)
+      myImage[(address & 0x7ff) + mySliceLow] = value;
+    else
+      myRAM[(address & 0x7ff) + mySliceLow] = value;
+  }
+  else if(((address & 0x1fff) >= 0x1800) &&  // 1.5K region from 0x1800 - 0x1dff
+          ((address & 0x1fff) <= 0x1dff))
+  {
+    if(myIsRomMiddle)
+      myImage[(address & 0x7ff) + mySliceMiddle + 0x10000] = value;
+    else
+      myRAM[(address & 0x7ff) + mySliceMiddle] = value;
+  }
+  else if((address & 0x1f00) == 0x1e00)      // 256B region from 0x1e00 - 0x1eff
+  {
+    if(myIsRomHigh)
+      myImage[(address & 0xff) + mySliceHigh + 0x10000] = value;
+    else
+      myRAM[(address & 0xff) + mySliceHigh] = value;
+  }
+  else if((address & 0x1f00) == 0x1f00)      // 256B region from 0x1f00 - 0x1fff
+  {
+    myImage[(address & 0xff) + 0x1ff00] = value;
+  }
+  return myBankChanged = true;
 } 
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
diff --git a/src/emucore/CartEFSC.cxx b/src/emucore/CartEFSC.cxx
index 8424bb7da..06e1eef82 100644
--- a/src/emucore/CartEFSC.cxx
+++ b/src/emucore/CartEFSC.cxx
@@ -176,7 +176,22 @@ int CartridgeEFSC::bankCount()
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 bool CartridgeEFSC::patch(uInt16 address, uInt8 value)
 {
-  myImage[(myCurrentBank << 12) + (address & 0x0FFF)] = value;
+  address &= 0x0FFF;
+
+  if(address < 0x0080)
+  {
+    myRAM[address] = value;
+  }
+  else if(address < 0x0100)
+  {
+    // Normally, a write to the read port won't do anything
+    // However, the patch command is special in that ignores such
+    // cart restrictions
+    myRAM[address - 0x80] = value;
+  }
+  else
+    myImage[(myCurrentBank << 12) + address] = value;
+
   return myBankChanged = true;
 } 
 
diff --git a/src/emucore/CartF4SC.cxx b/src/emucore/CartF4SC.cxx
index 4dd49fd87..de57c01cd 100644
--- a/src/emucore/CartF4SC.cxx
+++ b/src/emucore/CartF4SC.cxx
@@ -179,7 +179,22 @@ int CartridgeF4SC::bankCount()
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 bool CartridgeF4SC::patch(uInt16 address, uInt8 value)
 {
-  myImage[(myCurrentBank << 12) + (address & 0x0FFF)] = value;
+  address &= 0x0FFF;
+
+  if(address < 0x0080)
+  {
+    myRAM[address] = value;
+  }
+  else if(address < 0x0100)
+  {
+    // Normally, a write to the read port won't do anything
+    // However, the patch command is special in that ignores such
+    // cart restrictions
+    myRAM[address - 0x80] = value;
+  }
+  else
+    myImage[(myCurrentBank << 12) + address] = value;
+
   return myBankChanged = true;
 } 
 
diff --git a/src/emucore/CartF6SC.cxx b/src/emucore/CartF6SC.cxx
index 50ab59325..84c2b0c99 100644
--- a/src/emucore/CartF6SC.cxx
+++ b/src/emucore/CartF6SC.cxx
@@ -222,7 +222,22 @@ int CartridgeF6SC::bankCount()
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 bool CartridgeF6SC::patch(uInt16 address, uInt8 value)
 {
-  myImage[(myCurrentBank << 12) + (address & 0x0FFF)] = value;
+  address &= 0x0FFF;
+
+  if(address < 0x0080)
+  {
+    myRAM[address] = value;
+  }
+  else if(address < 0x0100)
+  {
+    // Normally, a write to the read port won't do anything
+    // However, the patch command is special in that ignores such
+    // cart restrictions
+    myRAM[address - 0x80] = value;
+  }
+  else
+    myImage[(myCurrentBank << 12) + address] = value;
+
   return myBankChanged = true;
 } 
 
diff --git a/src/emucore/CartF8SC.cxx b/src/emucore/CartF8SC.cxx
index e282b19f7..f67a6ec5f 100644
--- a/src/emucore/CartF8SC.cxx
+++ b/src/emucore/CartF8SC.cxx
@@ -202,7 +202,22 @@ int CartridgeF8SC::bankCount()
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 bool CartridgeF8SC::patch(uInt16 address, uInt8 value)
 {
-  myImage[(myCurrentBank << 12) + (address & 0x0FFF)] = value;
+  address &= 0x0FFF;
+
+  if(address < 0x0080)
+  {
+    myRAM[address] = value;
+  }
+  else if(address < 0x0100)
+  {
+    // Normally, a write to the read port won't do anything
+    // However, the patch command is special in that ignores such
+    // cart restrictions
+    myRAM[address - 0x80] = value;
+  }
+  else
+    myImage[(myCurrentBank << 12) + address] = value;
+
   return myBankChanged = true;
 } 
 
diff --git a/src/emucore/CartFA.cxx b/src/emucore/CartFA.cxx
index 08cd7f3dc..e88d97dc9 100644
--- a/src/emucore/CartFA.cxx
+++ b/src/emucore/CartFA.cxx
@@ -212,7 +212,22 @@ int CartridgeFA::bankCount()
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 bool CartridgeFA::patch(uInt16 address, uInt8 value)
 {
-  myImage[(myCurrentBank << 12) + (address & 0x0FFF)] = value;
+  address &= 0x0FFF;
+
+  if(address < 0x0100)
+  {
+    myRAM[address] = value;
+  }
+  else if(address < 0x0200)
+  {
+    // Normally, a write to the read port won't do anything
+    // However, the patch command is special in that ignores such
+    // cart restrictions
+    myRAM[address - 0x100] = value;
+  }
+  else
+    myImage[(myCurrentBank << 12) + address] = value;
+
   return myBankChanged = true;
 }