diff --git a/avr/usbload/Makefile b/avr/usbload/Makefile
index 48fe1b2..b6781dc 100644
--- a/avr/usbload/Makefile
+++ b/avr/usbload/Makefile
@@ -62,11 +62,8 @@ help:
 	@echo "make clean ..... to delete objects and hex file"
 
 hex: main.hex
-	@echo "==============================="
 	@echo "$(TARGET) compiled for: $(DEVICE)"
-	@echo -n "size is: "
-	@$(SIZE) -A $(TARGET).hex | grep "\.sec1" | tr -s " " | cut -d" " -f2
-	@echo "==============================="
+	@./checksize $(TARGET).elf
 
 program: flash fuse
 
diff --git a/avr/usbload/checksize b/avr/usbload/checksize
old mode 100644
new mode 100755
index 0751929..4a23d76
--- a/avr/usbload/checksize
+++ b/avr/usbload/checksize
@@ -5,11 +5,11 @@
 # Creation Date: 2004-12-29
 # Tabsize: 4
 # Copyright: (c) 2005 OBJECTIVE DEVELOPMENT Software GmbH.
-# Revision: $Id: checksize 83 2006-01-05 22:20:53Z cs $
+# Revision: $:Id: checksize 83 2006-01-05 22:20:53Z cs $
 
 error=0
-codelimit=16384  # default value
-datalimit=992   # default value; leave 32 bytes for stack
+codelimit=65536  # default value
+datalimit=4064   # default value; leave 32 bytes for stack
 
 if [ $# -gt 1 ]; then
 	codelimit="$2"
diff --git a/avr/usbload/shared_memory.c b/avr/usbload/shared_memory.c
index e53ee2f..fae03e7 100644
--- a/avr/usbload/shared_memory.c
+++ b/avr/usbload/shared_memory.c
@@ -38,6 +38,52 @@ uint8_t scratchpad_state;
 uint8_t scratchpad_cmd;
 uint8_t scratchpad_payload;
 
+uint8_t scratchpad_region_rx[SHARED_MEM_RX_LOC_SIZE];
+uint8_t scratchpad_region_tx[SHARED_MEM_TX_LOC_SIZE];
+
+uint8_t scratchpad_locked_rx = 1;
+uint8_t scratchpad_locked_tx = 1;
+
+
+void shared_memory_scratchpad_region_saye_helper(uint32_t addr){
+    
+    if(addr > (SHARED_MEM_TX_LOC_STATE +  SHARED_MEM_TX_LOC_SIZE ))
+        shared_memory_scratchpad_region_tx_save();
+    
+    if(addr > (SHARED_MEM_RX_LOC_STATE +  SHARED_MEM_RX_LOC_SIZE ))
+        shared_memory_scratchpad_region_rx_save();
+        }
+
+
+void shared_memory_scratchpad_region_tx_save()
+{
+    debug(DEBUG_SHM,"shared_memory_scratchpad_region_tx_save: unlock\n");
+    sram_bulk_read_buffer(SHARED_MEM_TX_LOC_STATE,scratchpad_region_tx,SHARED_MEM_TX_LOC_SIZE);
+    scratchpad_locked_tx = 0;
+}
+
+void shared_memory_scratchpad_region_tx_restore()
+{
+    debug(DEBUG_SHM,"shared_memory_scratchpad_region_tx_restore: lock\n");
+    sram_bulk_copy(SHARED_MEM_TX_LOC_STATE,scratchpad_region_tx,SHARED_MEM_TX_LOC_SIZE);
+    scratchpad_locked_tx = 1;
+}
+
+void shared_memory_scratchpad_region_rx_save()
+{
+    debug(DEBUG_SHM,"shared_memory_scratchpad_region_rx_save: unlock\n");
+    sram_bulk_read_buffer(SHARED_MEM_RX_LOC_STATE,scratchpad_region_rx,SHARED_MEM_RX_LOC_SIZE);
+    scratchpad_locked_rx = 0;
+}
+
+void shared_memory_scratchpad_region_rx_restore()
+{
+    debug(DEBUG_SHM,"shared_memory_scratchpad_region_tx_save: lock\n");
+    sram_bulk_copy(SHARED_MEM_RX_LOC_STATE,scratchpad_region_rx,SHARED_MEM_RX_LOC_SIZE);
+    scratchpad_locked_rx = 1;
+}
+
+
 void shared_memory_scratchpad_tx_save()
 {
     scratchpad_state = sram_read(SHARED_MEM_TX_LOC_STATE);
@@ -70,6 +116,9 @@ void shared_memory_irq_restore()
 void shared_memory_write(uint8_t cmd, uint8_t value)
 {
 
+    if (scratchpad_locked_tx) 
+        debug(DEBUG_SHM,"shared_memory_write:  locked_tx\n");
+    
     debug(DEBUG_SHM,"shared_memory_write:  0x%04x=0x%02x 0x%04x=0x%02x \n",
          SHARED_MEM_TX_LOC_CMD, cmd, SHARED_MEM_TX_LOC_PAYLOAD, value);
 
@@ -124,6 +173,9 @@ void shared_memory_yield()
 int shared_memory_read(uint8_t *cmd, uint8_t *len,uint8_t *buffer)
 {
     uint8_t state;
+    
+    if (scratchpad_locked_rx) 
+        debug(DEBUG_SHM,"shared_memory_write:  locked_tx\n");
 
 
     state = sram_read(SHARED_MEM_RX_LOC_STATE);
diff --git a/avr/usbload/shared_memory.h b/avr/usbload/shared_memory.h
index 8aff84c..c0d76c0 100644
--- a/avr/usbload/shared_memory.h
+++ b/avr/usbload/shared_memory.h
@@ -37,6 +37,7 @@
 #define SHARED_MEM_TX_CMD_TERMINATE         0x06
 
 #define SHARED_MEM_TX_LOC_STATE             0x000000
+#define SHARED_MEM_TX_LOC_SIZE              0x000100
 #define SHARED_MEM_TX_LOC_CMD               0x000001
 #define SHARED_MEM_TX_LOC_PAYLOAD           0x000002
 
@@ -47,6 +48,7 @@
 #define SHARED_MEM_RX_CMD_FILESEL           0x01
 
 #define SHARED_MEM_RX_LOC_STATE             0x001000
+#define SHARED_MEM_RX_LOC_SIZE              0x000400
 #define SHARED_MEM_RX_LOC_CMD               0x001001
 #define SHARED_MEM_RX_LOC_LEN               0x001002
 #define SHARED_MEM_RX_LOC_PAYLOAD           0x001003
@@ -60,6 +62,11 @@
 
 
 
+void shared_memory_scratchpad_region_saye_helper(uint32_t addr);
+void shared_memory_scratchpad_region_tx_save();
+void shared_memory_scratchpad_region_tx_restore();
+void shared_memory_scratchpad_region_rx_save();
+void shared_memory_scratchpad_region_rx_restore();
 void shared_memory_write(uint8_t cmd, uint8_t value);
 int shared_memory_read(uint8_t *cmd, uint8_t *len,uint8_t *buffer);