diff --git a/apps/tzreset/tzreset.c b/apps/tzreset/tzreset.c
index 4e6dddb..a175dd2 100644
--- a/apps/tzreset/tzreset.c
+++ b/apps/tzreset/tzreset.c
@@ -87,6 +87,7 @@ void usage(void)
     printf("  -h | --help              This help text.\n");
     printf("  -r | --reset             Perform a hardware reset.\n");
     printf("  -l | --load              Reload the default ROMS.\n");
+    printf("  -m | --memorymode <val>  Set the startup memory mode.\n");
     printf("\nOptions:-\n");
     printf("  -v | --verbose           Output more messages.\n");
 
@@ -111,6 +112,7 @@ uint32_t app(uint32_t param1, uint32_t param2)
     int        verbose_flag      = 0;
     int        opt; 
     int        option_index      = 0; 
+    uint8_t    memoryMode        = TZMM_ORIG;
     long       val               = 0;
     char      *argv[20];
     char      *ptr               = strtok((char *)param1, " ");
@@ -137,6 +139,7 @@ uint32_t app(uint32_t param1, uint32_t param2)
     {
         {"help",          no_argument,       0,   'h'},
         {"load",          no_argument,       0,   'l'},
+        {"memorymode",    required_argument, 0,   'm'},
         {"reset",         no_argument,       0,   'r'},
         {"verbose",       no_argument,       0,   'v'},
         {0,               0,                 0,    0}
@@ -144,7 +147,7 @@ uint32_t app(uint32_t param1, uint32_t param2)
 
     // Parse the command line options.
     //
-    while((opt = getopt_long(argc, argv, ":hlrv", long_options, &option_index)) != -1)  
+    while((opt = getopt_long(argc, argv, ":hlm:rv", long_options, &option_index)) != -1)  
     {  
         switch(opt)  
         {  
@@ -156,6 +159,15 @@ uint32_t app(uint32_t param1, uint32_t param2)
                 load_flag = 1;
                 break;
 
+            case 'm':
+                if(xatoi(&argv[optind-1], &val) == 0 || val >= 0x20)
+                {
+                    printf("Illegal numeric:%s\n", argv[optind-1]);
+                    return(1);
+                }
+                memoryMode = (uint8_t)val;
+                break;
+
             case 'r':
                 reset_flag = 1;
                 break;
@@ -180,17 +192,16 @@ uint32_t app(uint32_t param1, uint32_t param2)
         return(0);
     }
 
-    // Initialise the IO.
-    //setupZ80Pins(1, G->millis);
-
-    // Call the reset method to do the hard work.
+    // Reload the memory on the tranZPUter to boot default if load flag set.
     //
-    resetZ80();
-
-    // Reload the memory on the tranZPUter to boot default.
     if(load_flag)
     {
         loadTranZPUterDefaultROMS();
+    } else
+    {
+        // Call the reset method to do the hard work.
+        //
+        resetZ80(memoryMode);
     }
 
     return(0);
diff --git a/common/tranzputer.c b/common/tranzputer.c
index bf52e94..55cc234 100644
--- a/common/tranzputer.c
+++ b/common/tranzputer.c
@@ -532,7 +532,7 @@ void setupZ80Pins(uint8_t initK64F, volatile uint32_t *millisecondTick)
 
 // Method to reset the Z80 CPU.
 //
-void resetZ80(void)
+void resetZ80(uint8_t memoryMode)
 {
     // Locals.
     //
@@ -548,6 +548,13 @@ void resetZ80(void)
     pinInput(Z80_RESET);
     __enable_irq();
 
+    // Set the memory mode to the one provided.
+    //
+    if(memoryMode != TZMM_ORIG)
+    {
+        setCtrlLatch(memoryMode);
+    }
+
     // Wait a futher settling period before reinstating the interrupt.
     //
     while((*ms - startTime) < 400);
@@ -2083,14 +2090,11 @@ void loadTranZPUterDefaultROMS(void)
     //
     if(!result)
     {
-        // Set the memory model to BOOT so we can bootstrap TZFS.
-        setCtrlLatch(TZMM_BOOT);
-
         // If autoboot flag set, force a restart to the ROM which will call User ROM startup code.
         if(osControl.tzAutoBoot)
         {
-            delay(100);
-            fillZ80Memory(MZ_MROM_STACK_ADDR, MZ_MROM_STACK_SIZE, 0x00, 1);
+            // Set the memory model to BOOT so we can bootstrap TZFS.
+            resetZ80(TZMM_BOOT);
         }
 
         // No longer need refresh on the mainboard as all operations are in static RAM.
@@ -3722,7 +3726,7 @@ void processServiceRequest(void)
             z80Control.disableRefresh = 0;
            
             // Now reset the machine so everything starts as power on.
-            resetZ80();
+            resetZ80(TZMM_ORIG);
          
             // Disable the interrupts so no further service processing.
             disableIRQ();
@@ -3855,9 +3859,6 @@ void setupTranZPUter(void)
 
     // Check to see if autoboot is needed.
     osControl.tzAutoBoot = testTZFSAutoBoot();
-  
-    // Ensure the machine is ready by performing a RESET.
-    resetZ80();
 }
 
 //////////////////////////////////////////////////////////////
diff --git a/include/tranzputer.h b/include/tranzputer.h
index 3b12993..29da0ae 100755
--- a/include/tranzputer.h
+++ b/include/tranzputer.h
@@ -41,7 +41,7 @@
 #define RFSH_BYTE_CNT                256                                 // Number of bytes we can write before needing a full refresh for the DRAM.
 #define HOST_MON_TEST_VECTOR         0x4                                 // Address in the host monitor to test to identify host type.
 #define DEFAULT_BUSREQ_TIMEOUT       5000                                // Timeout for a Z80 Bus request operation in milliseconds.
-#define DEFAULT_RESET_PULSE_WIDTH    1000                                // Pulse width of a reset signal in |K4F clock ticks.
+#define DEFAULT_RESET_PULSE_WIDTH    80000                               // Pulse width of a reset signal in K64F clock ticks.
 
 // tranZPUter Memory Modes - select one of the 32 possible memory models using these constants.
 //
@@ -642,7 +642,7 @@ extern uint8_t                        pinMap[MAX_TRANZPUTER_PINS];
 void          yield(void);
 #endif
 void          setupZ80Pins(uint8_t, volatile uint32_t *);
-void          resetZ80(void);
+void          resetZ80(uint8_t);
 uint8_t       reqZ80Bus(uint32_t);
 uint8_t       reqMainboardBus(uint32_t);
 uint8_t       reqTranZPUterBus(uint32_t);
diff --git a/libraries/lib/libimath2-k64f.a b/libraries/lib/libimath2-k64f.a
index a5e750c..5c9b1ab 100644
Binary files a/libraries/lib/libimath2-k64f.a and b/libraries/lib/libimath2-k64f.a differ
diff --git a/libraries/lib/libumansi-k64f.a b/libraries/lib/libumansi-k64f.a
index 0a9f9cd..18d367a 100644
Binary files a/libraries/lib/libumansi-k64f.a and b/libraries/lib/libumansi-k64f.a differ
diff --git a/libraries/lib/libummath-k64f.a b/libraries/lib/libummath-k64f.a
index d96e7c6..a46cc14 100644
Binary files a/libraries/lib/libummath-k64f.a and b/libraries/lib/libummath-k64f.a differ
diff --git a/libraries/lib/libummathf-k64f.a b/libraries/lib/libummathf-k64f.a
index f6727c5..ec77e44 100644
Binary files a/libraries/lib/libummathf-k64f.a and b/libraries/lib/libummathf-k64f.a differ
diff --git a/libraries/lib/libummisc-k64f.a b/libraries/lib/libummisc-k64f.a
index b673787..2383c97 100644
Binary files a/libraries/lib/libummisc-k64f.a and b/libraries/lib/libummisc-k64f.a differ
diff --git a/libraries/lib/libumstdio-k64f.a b/libraries/lib/libumstdio-k64f.a
index 09ba09d..6a77f48 100644
Binary files a/libraries/lib/libumstdio-k64f.a and b/libraries/lib/libumstdio-k64f.a differ
diff --git a/zOS/src/zOS.cpp b/zOS/src/zOS.cpp
index d353c18..bfe1242 100644
--- a/zOS/src/zOS.cpp
+++ b/zOS/src/zOS.cpp
@@ -253,9 +253,6 @@ void tranZPUterControl(void)
         //
         if(isZ80Reset())
         {
-            // Reset Z80 - This is to extend the reset signal to allow all the CPLD's/FPGA's to sync.
-            resetZ80();
-
             // Reload the memory on the tranZPUter to boot default.
             loadTranZPUterDefaultROMS();