diff --git a/avr/usbload/crc.c b/avr/usbload/crc.c
index c7e0100..9d58925 100644
--- a/avr/usbload/crc.c
+++ b/avr/usbload/crc.c
@@ -16,7 +16,6 @@ uint16_t crc_xmodem_update(uint16_t crc, uint8_t data)
         else
             crc <<= 1;
     }
-
     return crc;
 }
 
@@ -26,7 +25,6 @@ uint16_t do_crc(uint8_t * data, uint16_t size)
     uint16_t i;
     for (i = 0; i < size; i++) {
         crc = crc_xmodem_update(crc, data[i]);
-        // printf("%x : %x\n",crc,data[i]); 
     }
     return crc;
 }
diff --git a/avr/usbload/main.c b/avr/usbload/main.c
index 5c6b631..9209135 100644
--- a/avr/usbload/main.c
+++ b/avr/usbload/main.c
@@ -135,7 +135,7 @@ usbMsgLen_t usbFunctionSetup(uchar data[8])
         printf("USB_CRC_ADDR: Addr: 0x%lx Size: %li\n", req_addr, req_size);
 #endif
         cli();
-        // crc_check_memory_range(req_addr,req_size);
+        crc_check_memory_range(req_addr,req_size);
         sei();
         ret_len = 2;
     }
diff --git a/avr/usbload/sram.c b/avr/usbload/sram.c
index 1f32d3c..d2367a9 100644
--- a/avr/usbload/sram.c
+++ b/avr/usbload/sram.c
@@ -97,16 +97,64 @@ void sreg_set(uint32_t addr)
 }
 
 
+void sram_bulk_read_start(uint32_t addr)
+{
+#ifdef DEBUG_SRAM
+    printf("sram_bulk_read_start: addr=0x%08lx\n\r", addr);
+#endif
+    avr_data_in();
+
+    AVR_WR_PORT |= (1 << AVR_WR_PIN);
+    AVR_RD_PORT |= (1 << AVR_RD_PIN);
+    AVR_CS_PORT &= ~(1 << AVR_CS_PIN);
+    sreg_set(addr);
+
+    AVR_RD_PORT &= ~(1 << AVR_RD_PIN);
+
+}
+
+void sram_bulk_read_end(void)
+{
+#ifdef DEBUG_SRAM
+    printf("sram_bulk_read_end:");
+#endif
+    AVR_CS_PORT |= (1 << AVR_CS_PIN);
+    avr_data_in();
+}
+
+inline uint8_t sram_bulk_read(void)
+{
+    uint8_t byte;
+    AVR_RD_PORT |= (1 << AVR_RD_PIN);
+    counter_up();
+    AVR_RD_PORT &= ~(1 << AVR_RD_PIN);
+
+    asm volatile ("nop");
+    asm volatile ("nop");
+    asm volatile ("nop");
+    asm volatile ("nop");
+    asm volatile ("nop");
+    asm volatile ("nop");
+    asm volatile ("nop");
+    asm volatile ("nop");
+
+    byte = AVR_DATA_PIN;
+    AVR_RD_PORT |= (1 << AVR_RD_PIN);
+    return byte;
+}
 
 uint8_t sram_read(uint32_t addr)
 {
     uint8_t byte;
+#ifdef DEBUG_SRAM
+    printf("sram_read: addr=0x%08lx\n\r", addr);
+#endif
     
     avr_data_in();
     
+    AVR_CS_PORT &= ~(1 << AVR_CS_PIN);
     AVR_WR_PORT |= (1 << AVR_WR_PIN);
     AVR_RD_PORT |= (1 << AVR_RD_PIN);
-    AVR_CS_PORT &= ~(1 << AVR_CS_PIN);
     
     sreg_set(addr);
     
@@ -133,6 +181,11 @@ uint8_t sram_read(uint32_t addr)
 
 void sram_write(uint32_t addr, uint8_t data)
 {
+
+#ifdef DEBUG_SRAM
+    printf("sram_write: addr=0x%08lx data=%x\n\r", addr, data);
+#endif
+
     avr_data_out();
     
     AVR_CS_PORT &= ~(1 << AVR_CS_PIN);
diff --git a/avr/usbload/sram.h b/avr/usbload/sram.h
index 5252425..0277409 100644
--- a/avr/usbload/sram.h
+++ b/avr/usbload/sram.h
@@ -141,9 +141,15 @@
 
 void system_init(void);
 void sreg_set(uint32_t addr);
+
 uint8_t sram_read(uint32_t addr);
 void sram_write(uint32_t addr, uint8_t data);
 void sram_clear(uint32_t addr, uint32_t len);
 void sram_copy(uint32_t addr,uint8_t *src, uint32_t len);
+
+void sram_bulk_read_start(uint32_t addr);
+void sram_bulk_read_end(void);
+uint8_t sram_bulk_read(void);
+
 void sram_read_buffer(uint32_t addr,uint8_t *dst, uint32_t len);
 uint8_t sram_check(uint8_t *buffer, uint32_t len);