diff --git a/src/NDS.cpp b/src/NDS.cpp
index bdb0c2d0..df9ed331 100644
--- a/src/NDS.cpp
+++ b/src/NDS.cpp
@@ -1456,7 +1456,7 @@ u8 ARM9IORead8(u32 addr)
         return GPU3D::Read8(addr);
     }
 
-    printf("unknown ARM9 IO read8 %08X\n", addr);
+    printf("unknown ARM9 IO read8 %08X %08X\n", addr, ARM9->R[15]);
     return 0;
 }
 
@@ -1694,7 +1694,7 @@ u32 ARM9IORead32(u32 addr)
         return GPU3D::Read32(addr);
     }
 
-    printf("unknown ARM9 IO read32 %08X\n", addr);
+    printf("unknown ARM9 IO read32 %08X %08X\n", addr, ARM9->R[15]);
     return 0;
 }
 
@@ -1774,7 +1774,7 @@ void ARM9IOWrite8(u32 addr, u8 val)
         return;
     }
 
-    printf("unknown ARM9 IO write8 %08X %02X\n", addr, val);
+    printf("unknown ARM9 IO write8 %08X %02X %08X\n", addr, val, ARM9->R[15]);
 }
 
 void ARM9IOWrite16(u32 addr, u16 val)
@@ -1935,7 +1935,7 @@ void ARM9IOWrite16(u32 addr, u16 val)
         return;
     }
 
-    printf("unknown ARM9 IO write16 %08X %04X %08X\n", addr, val, ARM9->R[14]);
+    printf("unknown ARM9 IO write16 %08X %04X %08X\n", addr, val, ARM9->R[15]);
 }
 
 void ARM9IOWrite32(u32 addr, u32 val)
@@ -2088,7 +2088,7 @@ void ARM9IOWrite32(u32 addr, u32 val)
         return;
     }
 
-    printf("unknown ARM9 IO write32 %08X %08X\n", addr, val);
+    printf("unknown ARM9 IO write32 %08X %08X %08X\n", addr, val, ARM9->R[15]);
 }
 
 
@@ -2133,7 +2133,7 @@ u8 ARM7IORead8(u32 addr)
         return SPU::Read8(addr);
     }
 
-    printf("unknown ARM7 IO read8 %08X\n", addr);
+    printf("unknown ARM7 IO read8 %08X %08X\n", addr, ARM7->R[15]);
     return 0;
 }
 
@@ -2210,7 +2210,7 @@ u16 ARM7IORead16(u32 addr)
         return SPU::Read16(addr);
     }
 
-    printf("unknown ARM7 IO read16 %08X %08X\n", addr, ARM9->R[15]);
+    printf("unknown ARM7 IO read16 %08X %08X\n", addr, ARM7->R[15]);
     return 0;
 }
 
@@ -2296,7 +2296,7 @@ u32 ARM7IORead32(u32 addr)
         return SPU::Read32(addr);
     }
 
-    printf("unknown ARM7 IO read32 %08X\n", addr);
+    printf("unknown ARM7 IO read32 %08X %08X\n", addr, ARM7->R[15]);
     return 0;
 }
 
@@ -2368,7 +2368,7 @@ void ARM7IOWrite8(u32 addr, u8 val)
         return;
     }
 
-    printf("unknown ARM7 IO write8 %08X %02X\n", addr, val);
+    printf("unknown ARM7 IO write8 %08X %02X %08X\n", addr, val, ARM7->R[15]);
 }
 
 void ARM7IOWrite16(u32 addr, u16 val)
@@ -2489,7 +2489,7 @@ void ARM7IOWrite16(u32 addr, u16 val)
         return;
     }
 
-    printf("unknown ARM7 IO write16 %08X %04X\n", addr, val);
+    printf("unknown ARM7 IO write16 %08X %04X %08X\n", addr, val, ARM7->R[15]);
 }
 
 void ARM7IOWrite32(u32 addr, u32 val)
@@ -2591,7 +2591,7 @@ void ARM7IOWrite32(u32 addr, u32 val)
         return;
     }
 
-    printf("unknown ARM7 IO write32 %08X %08X\n", addr, val);
+    printf("unknown ARM7 IO write32 %08X %08X %08X\n", addr, val, ARM7->R[15]);
 }
 
 }