diff --git a/BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Via.Registers.cs b/BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Via.Registers.cs
index 8e354c89e3..1215121257 100644
--- a/BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Via.Registers.cs
+++ b/BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Via.Registers.cs
@@ -58,7 +58,7 @@
 				case 0x0:
 					return _port.ReadPrb(_prb, _ddrb);
 				case 0x1:
-					return _port.ReadPra(_pra, _ddra);
+					return _port.ReadExternalPra();
 				case 0x2:
 					return _ddrb;
 				case 0x3:
@@ -86,7 +86,7 @@
 				case 0xE:
 					return _ier | 0x80;
 				case 0xF:
-					return _port.ReadPra(_pra, _ddra);
+					return _port.ReadExternalPra();
 			}
 
 			return 0xFF;
@@ -238,7 +238,7 @@
 
 		public int EffectivePrB => _prb | ~_ddrb;
 
-		public int ActualPrA => _acrPaLatchEnable ? _paLatch : _port.ReadPra(_pra, _ddra);
+		public int ActualPrA => _acrPaLatchEnable ? _paLatch : _port.ReadExternalPra();
 
 		public int ActualPrB => _acrPbLatchEnable ? _pbLatch : _port.ReadPrb(_prb, _ddrb);
 	}
diff --git a/BizHawk.Emulation.Cores/Computers/Commodore64/Media/D64.cs b/BizHawk.Emulation.Cores/Computers/Commodore64/Media/D64.cs
index 082fc32b0a..f086bb3b21 100644
--- a/BizHawk.Emulation.Cores/Computers/Commodore64/Media/D64.cs
+++ b/BizHawk.Emulation.Cores/Computers/Commodore64/Media/D64.cs
@@ -248,9 +248,9 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.Media
                         trackDensities.Add(DensityTable[i]);
                     }
                 }
-                
-                return new Disk(trackDatas, trackNumbers, trackDensities, 84);
-            }
+
+				return new Disk(trackDatas, trackNumbers, trackDensities, 84) {WriteProtected = false};
+			}
         }
 	}
 }
diff --git a/BizHawk.Emulation.Cores/Computers/Commodore64/Media/G64.cs b/BizHawk.Emulation.Cores/Computers/Commodore64/Media/G64.cs
index bceb344add..74f3fd2045 100644
--- a/BizHawk.Emulation.Cores/Computers/Commodore64/Media/G64.cs
+++ b/BizHawk.Emulation.Cores/Computers/Commodore64/Media/G64.cs
@@ -57,10 +57,10 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.Media
 						throw new Exception("Byte-level speeds are not yet supported in the G64 loader.");
 					}
 
-					return new Disk(trackDatas, trackNumbers, trackDensities, 84);
+					return new Disk(trackDatas, trackNumbers, trackDensities, 84) {WriteProtected = true};
 				}
 
-				return new Disk(84);
+				return new Disk(84) {WriteProtected = false};
 			}
 		}
 		
diff --git a/BizHawk.Emulation.Cores/Computers/Commodore64/Serial/Drive1541.FluxTransitions.cs b/BizHawk.Emulation.Cores/Computers/Commodore64/Serial/Drive1541.FluxTransitions.cs
index 2cdd555caf..0f9a3782c5 100644
--- a/BizHawk.Emulation.Cores/Computers/Commodore64/Serial/Drive1541.FluxTransitions.cs
+++ b/BizHawk.Emulation.Cores/Computers/Commodore64/Serial/Drive1541.FluxTransitions.cs
@@ -72,7 +72,7 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.Serial
                     }
                     _diskOutputBits >>= 1;
 
-                    if (_diskWriteEnabled)
+                    if (_diskWriteEnabled && !_diskWriteProtected)
                         _countsBeforeRandomTransition = 0;
 
                     if ((_diskBits & 1) != 0)
diff --git a/BizHawk.Emulation.Cores/Computers/Commodore64/Serial/Drive1541.cs b/BizHawk.Emulation.Cores/Computers/Commodore64/Serial/Drive1541.cs
index afe069f236..50fb387ecb 100644
--- a/BizHawk.Emulation.Cores/Computers/Commodore64/Serial/Drive1541.cs
+++ b/BizHawk.Emulation.Cores/Computers/Commodore64/Serial/Drive1541.cs
@@ -214,6 +214,11 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.Serial
 			{
 				_trackImageData = _disk.GetDataForTrack(_trackNumber);
 				_diskBits = _trackImageData[_diskByteOffset] >> (Disk.FluxBitsPerEntry - _diskBitsLeft);
+				_diskWriteProtected = _disk.WriteProtected;
+			}
+			else
+			{
+				_diskWriteProtected = true;
 			}
 		}