diff --git a/bochs/cpu/fetchdecode.cc b/bochs/cpu/fetchdecode.cc
index 315f4054a..35da1a6be 100644
--- a/bochs/cpu/fetchdecode.cc
+++ b/bochs/cpu/fetchdecode.cc
@@ -1,5 +1,5 @@
 /////////////////////////////////////////////////////////////////////////
-// $Id: fetchdecode.cc,v 1.196 2008-07-13 15:35:09 sshwarts Exp $
+// $Id: fetchdecode.cc,v 1.197 2008-08-09 19:18:09 sshwarts Exp $
 /////////////////////////////////////////////////////////////////////////
 //
 //  Copyright (C) 2001  MandrakeSoft S.A.
@@ -2488,7 +2488,6 @@ fetch_b1:
 
   switch (b1) {
     case 0x0f: // 2-byte escape
-      i->setOpcodeExtension();
       if (ilen < remain) {
         ilen++;
         b1 = 0x100 | *iptr++;
@@ -2947,9 +2946,13 @@ modrm_done:
 
 void BX_CPP_AttrRegparmN(1) BX_CPU_C::BxError(bxInstruction_c *i)
 {
-  BX_DEBUG(("BxError: i with opcode=0x%u%02x", i->hasOpcodeExtension(), i->b1()));
+  BX_DEBUG(("BxError: Encountered an unknown instruction b1=0x%02x (signalling #UD)", i->b1()));
   BX_DEBUG(("modrm was 0x%02x, nnn was %u, rm was %u", i->modrm(), i->nnn(), i->rm()));
-  BX_DEBUG(("WARNING: Encountered an unknown instruction (signalling #UD)"));
+
+#if BX_DISASM && BX_DEBUGGER == 0 // with debugger it easy to see the #UD
+  if (LOG_THIS getonoff(LOGLEV_DEBUG))
+    debug_disasm_instruction(BX_CPU_THIS_PTR prev_rip);
+#endif
 
   exception(BX_UD_EXCEPTION, 0, 0);
 }
diff --git a/bochs/cpu/fetchdecode64.cc b/bochs/cpu/fetchdecode64.cc
index 3a000c50e..05794220c 100644
--- a/bochs/cpu/fetchdecode64.cc
+++ b/bochs/cpu/fetchdecode64.cc
@@ -1,5 +1,5 @@
 /////////////////////////////////////////////////////////////////////////
-// $Id: fetchdecode64.cc,v 1.204 2008-07-13 09:59:59 sshwarts Exp $
+// $Id: fetchdecode64.cc,v 1.205 2008-08-09 19:18:09 sshwarts Exp $
 /////////////////////////////////////////////////////////////////////////
 //
 //  Copyright (C) 2001  MandrakeSoft S.A.
@@ -3398,7 +3398,6 @@ fetch_b1:
       }
       return(0);
     case 0x0f: // 2 byte escape
-      i->setOpcodeExtension();
       if (ilen < remain) {
         ilen++;
         b1 = 0x100 | *iptr++;
diff --git a/bochs/cpu/instr.h b/bochs/cpu/instr.h
index 66f26574c..5daeb231c 100755
--- a/bochs/cpu/instr.h
+++ b/bochs/cpu/instr.h
@@ -1,5 +1,5 @@
 /////////////////////////////////////////////////////////////////////////
-// $Id: instr.h,v 1.14 2008-08-08 09:22:47 sshwarts Exp $
+// $Id: instr.h,v 1.15 2008-08-09 19:18:09 sshwarts Exp $
 /////////////////////////////////////////////////////////////////////////
 //
 //   Copyright (c) 2008 Stanislav Shwartsman
@@ -50,9 +50,8 @@ public:
 #endif
 
   struct {
-    //  7...2 (unused)
-    //  1...1 stop trace (used with trace cache)
-    //  0...0 opcode extension: 0-none, 1-0x0f used
+    //  7...1 (unused)
+    //  0...0 stop trace (used with trace cache)
     Bit8u metaInfo4;
 
     //  7...0 b1 - opcode byte
@@ -274,19 +273,12 @@ public:
     metaInfo.metaInfo3 = b1 & 0xff;
   }
 
-  BX_CPP_INLINE void setOpcodeExtension(void) {
-    metaInfo.metaInfo4 |= 1;
-  }
-  BX_CPP_INLINE unsigned hasOpcodeExtension(void) const {
-    return metaInfo.metaInfo4 & 1;
-  }
-
 #if BX_SUPPORT_TRACE_CACHE
   BX_CPP_INLINE void setStopTraceAttr(void) {
-   metaInfo.metaInfo4 |= (1<<1);
+   metaInfo.metaInfo4 |= 1;
   }
   BX_CPP_INLINE unsigned getStopTraceAttr(void) const {
-    return metaInfo.metaInfo4 & (1<<1);
+    return metaInfo.metaInfo4 & 1;
   }
 #endif
 };
diff --git a/bochs/cpu/proc_ctrl.cc b/bochs/cpu/proc_ctrl.cc
index f318ef652..467b93f5d 100644
--- a/bochs/cpu/proc_ctrl.cc
+++ b/bochs/cpu/proc_ctrl.cc
@@ -1,5 +1,5 @@
 /////////////////////////////////////////////////////////////////////////
-// $Id: proc_ctrl.cc,v 1.251 2008-08-08 09:22:47 sshwarts Exp $
+// $Id: proc_ctrl.cc,v 1.252 2008-08-09 19:18:09 sshwarts Exp $
 /////////////////////////////////////////////////////////////////////////
 //
 //  Copyright (C) 2001  MandrakeSoft S.A.
@@ -41,7 +41,7 @@
 
 void BX_CPP_AttrRegparmN(1) BX_CPU_C::UndefinedOpcode(bxInstruction_c *i)
 {
-  BX_DEBUG(("UndefinedOpcode: 0x%d%02x causes #UD exception", i->hasOpcodeExtension(), i->b1()));
+  BX_DEBUG(("UndefinedOpcode: b1 = 0x%02x causes #UD exception", i->b1()));
   exception(BX_UD_EXCEPTION, 0, 0);
 }