diff --git a/Makefile b/Makefile
index fee59e3..aea1ae8 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
 OBJS = jedec.o sst28sf040.o am29f040b.o mx29f002.c sst39sf020.o m29f400bt.o \
-	w49f002u.o 82802ab.o msys_doc.o pm49fl004.o
+	w49f002u.o 82802ab.o msys_doc.o pm49fl004.o sst49lf040.o
 CC = gcc -O2 -g -Wall -Werror
 
 all: flash_rom flash_on
@@ -15,7 +15,7 @@
 
 flash_rom.o: flash_rom.c flash.h jedec.h \
 	82802ab.h am29f040b.h m29f400bt.h msys_doc.h mx29f002.h sst28sf040.h \
-	sst39sf020.h w49f002u.h
+	sst39sf020.h w49f002u.h sst49lf040.h
 flash_on.o: flash_on.c
 
 82802ab.o:    82802ab.c    82802ab.h            flash.h
@@ -25,6 +25,7 @@
 mx29f002.o:   mx29f002.c   mx29f002.h   jedec.h flash.h
 sst28sf040.o: sst28sf040.c sst28sf040.h jedec.h flash.h
 sst39sf020.o: sst39sf020.c sst39sf020.h jedec.h flash.h
+sst49lf040.o: sst49lf040.c sst49lf040.h jedec.h flash.h
 w49f002u.o:   w49f002u.c   w49f002u.h   jedec.h flash.h
 pm49fl004.o:   pm49fl004.c   pm49fl004.h   jedec.h flash.h
 
diff --git a/flash.h b/flash.h
index ace46a4..f4a3d22 100644
--- a/flash.h
+++ b/flash.h
@@ -35,7 +35,8 @@
 #define SST_29EE020A      0x10	/* SST 29EE020 device code	*/
 #define SST_28SF040       0x04    /* SST 29EE040 device code	*/
 #define SST_39SF020       0xB6    /* SST 39SF020  device        */
-#define SST_39VF020       0xD6    /* SST 39SF020  device        */
+#define SST_39VF020       0xD6    /* SST 39VF020  device        */
+#define SST_49LF040	  0x51	/* SST 49LF040 device */
 
 #define PMC_ID            0x9D  /* PMC Manufacturer ID[B code   */
 #define PMC_49FL004       0x6E  /* PMC 49FL004 device code      */
diff --git a/flash_rom.c b/flash_rom.c
index b063b3c..b476d35 100644
--- a/flash_rom.c
+++ b/flash_rom.c
@@ -46,6 +46,7 @@
 #include "sst28sf040.h"
 #include "w49f002u.h"
 #include "sst39sf020.h"
+#include "sst49lf040.h"
 #include "pm49fl004.h"
 #include "mx29f002.h"
 
@@ -65,6 +66,9 @@
      probe_39sf020, erase_39sf020, write_39sf020, NULL},
     {"SST39VF020",  SST_ID,     SST_39VF020,  NULL, 256, 4096,
      probe_39sf020, erase_39sf020, write_39sf020, NULL},
+    {"SST49LF040",  SST_ID,	SST_49LF040,  NULL, 512, 4096,
+     probe_49lf040, erase_49lf040, write_49lf040, NULL},
+
 #endif
 //By LYH begin
     {"Pm49FL004",  PMC_ID,     PMC_49FL004,  NULL, 512, 64*1024,
@@ -373,7 +377,8 @@
 	 		flash->total_size * 1024, (unsigned long)size);
 	}
 	bios = mmap (0, size, PROT_WRITE | PROT_READ, MAP_SHARED,
-		     fd_mem, (off_t) (0-size));
+		     //fd_mem, (off_t) (0x100000000-size));
+		     fd_mem, (off_t) (0x0-size));
 	if (bios == MAP_FAILED) {
 	    perror("Error MMAP /dev/mem");
 	    exit(1);
diff --git a/sst49lf040.c b/sst49lf040.c
new file mode 100644
index 0000000..9899e44
--- /dev/null
+++ b/sst49lf040.c
@@ -0,0 +1,224 @@
+/* sst40lf020.c: driver for SST40LF040 flash models.
+ *
+ *
+ * Copyright 2000 Silicon Integrated System Corporation
+ *
+ *      This program is free software; you can redistribute it and/or modify
+ *      it under the terms of the GNU General Public License as published by
+ *      the Free Software Foundation; either version 2 of the License, or
+ *      (at your option) any later version.
+ *
+ *      This program is distributed in the hope that it will be useful,
+ *      but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *      GNU General Public License for more details.
+ *
+ *      You should have received a copy of the GNU General Public License
+ *      along with this program; if not, write to the Free Software
+ *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ *
+ * Reference:
+ *      4 MEgabit (512K x 8) SuperFlash EEPROM, SST49lF040 data sheet
+ *
+ * $Id$
+ */
+			 
+
+#include <stdio.h>
+#include "flash.h"
+#include "jedec.h"
+#include "sst49lf040.h"
+
+#define AUTO_PG_ERASE1		0x20
+#define AUTO_PG_ERASE2		0xD0
+#define AUTO_PGRM		0x10
+#define CHIP_ERASE		0x30
+#define RESET			0xFF
+#define READ_ID			0x90
+
+static __inline__ void protect_49lf040 (volatile char * bios)
+{
+	/* ask compiler not to optimize this */
+	volatile unsigned char tmp;
+
+	tmp = *(volatile unsigned char *) (bios + 0x1823);
+	tmp = *(volatile unsigned char *) (bios + 0x1820);
+	tmp = *(volatile unsigned char *) (bios + 0x1822);
+	tmp = *(volatile unsigned char *) (bios + 0x0418);
+	tmp = *(volatile unsigned char *) (bios + 0x041B);
+	tmp = *(volatile unsigned char *) (bios + 0x0419);
+	tmp = *(volatile unsigned char *) (bios + 0x040A);
+}
+
+static __inline__ void unprotect_49lf040 (volatile char * bios)
+{
+	/* ask compiler not to optimize this */
+	volatile unsigned char tmp;
+
+	tmp = *(volatile unsigned char *) (bios + 0x1823);
+	tmp = *(volatile unsigned char *) (bios + 0x1820);
+	tmp = *(volatile unsigned char *) (bios + 0x1822);
+	tmp = *(volatile unsigned char *) (bios + 0x0418);
+	tmp = *(volatile unsigned char *) (bios + 0x041B);
+	tmp = *(volatile unsigned char *) (bios + 0x0419);
+	tmp = *(volatile unsigned char *) (bios + 0x041A);
+}
+
+int erase_sector_49lf040 (volatile char * bios, unsigned int page)
+{
+	/* Chip erase function does not exist for LPC mode on 49lf040.
+	 * Erase sector-by-sector instead. */
+	volatile unsigned char *Temp;
+
+        /*  Issue the Sector Erase command to 40LF040   */
+        Temp  = bios + 0x5555; /* set up address to be C000:5555h      */
+        *Temp = 0xAA;            /* write data 0xAA to the address       */
+	myusec_delay(10);
+        Temp  = bios + 0x2AAA; /* set up address to be C000:2AAAh      */
+        *Temp = 0x55;         /* write data 0x55 to the address       */
+	myusec_delay(10);
+        Temp  = bios + 0x5555; /* set up address to be C000:5555h      */
+        *Temp = 0x80;            /* write data 0x80 to the address       */
+	myusec_delay(10);
+        Temp  = bios + 0x5555; /* set up address to be C000:5555h      */
+        *Temp = 0xAA;         /* write data 0xAA to the address       */
+	myusec_delay(10);
+        Temp  = bios + 0x2AAA; /* set up address to be C000:2AAAh      */
+        *Temp = 0x55;          /* write data 0x55 to the address       */
+	myusec_delay(10);
+        Temp  = bios + page; /* set up address to be the current sector */
+        *Temp = 0x30;       /* write data 0x30 to the address       */
+	myusec_delay(25000);
+	
+	/* wait for Toggle bit ready         */
+	toggle_ready_jedec(bios);
+	myusec_delay(25000);
+
+	return(0);
+}
+
+static __inline__ int write_sector_49lf040(volatile char * bios, 
+				       unsigned char * src,
+				       volatile unsigned char * dst, 
+				       unsigned int page_size)
+{
+	int i;
+	volatile char *Temp;
+
+	for (i = 0; i < page_size; i++) {
+		if (*dst != 0xff) {
+			printf("FATAL: dst %p not erased (val 0x%x)\n", dst, *dst);
+			return(-1);
+		}
+		/* transfer data from source to destination */
+		if (*src == 0xFF) {
+			dst++, src++;
+			/* If the data is 0xFF, don't program it */
+			continue;
+		}
+		Temp =   (bios + 0x5555); 
+		*Temp = 0xAA;                   
+		Temp =  bios + 0x2AAA; 
+		*Temp = 0x55; 
+		Temp =  bios + 0x5555; 
+		*Temp = 0xA0;                   
+		*dst = *src;
+		toggle_ready_jedec(bios);
+
+	        data_polling_jedec(dst, *src);
+		if (*dst != *src)
+			printf("BAD! dst 0x%lx val 0x%x src 0x%x\n",
+			       (unsigned long)dst, *dst, *src);
+		dst++, src++;
+	}
+
+	return(0);
+}
+
+int probe_49lf040 (struct flashchip * flash)
+{
+        volatile char * bios = flash->virt_addr;
+        unsigned char  id1, id2;
+
+        *(volatile char *) (bios + 0x5555) = 0xAA;
+        myusec_delay(10);
+        *(volatile char *) (bios + 0x2AAA) = 0x55;
+        myusec_delay(10);
+        *(volatile char *) (bios + 0x5555) = 0x90;
+
+        myusec_delay(10);
+
+        id1 = *(volatile unsigned char *) bios;
+        id2 = *(volatile unsigned char *) (bios + 0x01);
+
+        *(volatile char *) (bios + 0x5555) = 0xAA;
+        *(volatile char *) (bios + 0x2AAA) = 0x55;
+        *(volatile char *) (bios + 0x5555) = 0xF0;
+
+        myusec_delay(10);
+
+	printf("%s: id1 0x%x, id2 0x%x\n", __FUNCTION__, id1, id2);
+
+        if (id1 == flash->manufacture_id && id2 == flash->model_id)
+                return 1;
+
+        return 0;
+}
+/* Chip erase only works in parallel programming mode for the 49lf040.
+ * Use sector-erase instead */
+int erase_49lf040 (struct flashchip * flash)
+{
+	volatile unsigned char * bios = flash->virt_addr;
+	volatile unsigned char *Temp;
+
+        /*  Issue the Sector Erase command to 40LF040   */
+        Temp  = bios + 0x5555; /* set up address to be C000:5555h      */
+        *Temp = 0xAA;            /* write data 0xAA to the address       */
+	myusec_delay(10);
+        Temp  = bios + 0x2AAA; /* set up address to be C000:2AAAh      */
+        *Temp = 0x55;         /* write data 0x55 to the address       */
+	myusec_delay(10);
+        Temp  = bios + 0x5555; /* set up address to be C000:5555h      */
+        *Temp = 0x80;            /* write data 0x80 to the address       */
+	myusec_delay(10);
+        Temp  = bios + 0x5555; /* set up address to be C000:5555h      */
+        *Temp = 0xAA;         /* write data 0xAA to the address       */
+	myusec_delay(10);
+        Temp  = bios + 0x2AAA; /* set up address to be C000:2AAAh      */
+        *Temp = 0x55;          /* write data 0x55 to the address       */
+	myusec_delay(10);
+        Temp  = bios + 0x5555; /* set up address to be C000:5555h      */
+        *Temp = 0x10;       /* write data 0x55 to the address       */
+	
+	myusec_delay(50000);
+
+	return(0);
+}
+
+int write_49lf040 (struct flashchip * flash, unsigned char * buf)
+{
+	int i;
+	int total_size = flash->total_size * 1024, page_size = flash->page_size;
+	volatile char * bios = flash->virt_addr;
+
+//	unprotect_49lf040 (bios);
+//	erase_49lf040(flash); /* Must be done sector-by-sector in LPC mode */
+	printf ("Programming Page: ");
+	for (i = 0; i < total_size/page_size; i++) {
+		/* erase the page before programming */
+		erase_sector_49lf040(bios, i * page_size);
+
+		/* write to the sector */
+		printf ("%04d at address: 0x%08x ", i, i * page_size);
+		write_sector_49lf040(bios, buf + i * page_size, bios + i * page_size,
+				     page_size);
+		printf ("\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b");
+                fflush(stdout);
+	}
+	printf("\n");
+
+//	protect_49lf040 (bios);
+
+	return(0);
+}
diff --git a/sst49lf040.h b/sst49lf040.h
new file mode 100644
index 0000000..292ebe9
--- /dev/null
+++ b/sst49lf040.h
@@ -0,0 +1,8 @@
+#ifndef __SST49LF040_H__
+#define __SST49LF040_H__ 1
+
+extern int probe_49lf040 (struct flashchip * flash);
+extern int erase_49lf040 (struct flashchip * flash);
+extern int write_49lf040 (struct flashchip * flash, unsigned char * buf);
+
+#endif /* !__SST49LF040_H__ */