diff --git a/Makefile b/Makefile
index 9184bb3..5573127 100644
--- a/Makefile
+++ b/Makefile
@@ -514,7 +514,7 @@
 CHIP_OBJS = jedec.o stm50.o w39.o w29ee011.o \
 	sst28sf040.o 82802ab.o \
 	sst49lfxxxc.o sst_fwhub.o flashchips.o spi.o spi25.o spi25_statusreg.o \
-	opaque.o sfdp.o en29lv640b.o at45db.o
+	spi4ba.o opaque.o sfdp.o en29lv640b.o at45db.o
 
 ###############################################################################
 # Library code.
diff --git a/chipdrivers.h b/chipdrivers.h
index c85eac9..dccd1ff 100644
--- a/chipdrivers.h
+++ b/chipdrivers.h
@@ -195,4 +195,14 @@
 int probe_en29lv640b(struct flashctx *flash);
 int write_en29lv640b(struct flashctx *flash, const uint8_t *buf, unsigned int start, unsigned int len);
 
+/* spi4ba.c */
+int spi_enter_4ba_b7(struct flashctx *flash);
+int spi_enter_4ba_b7_we(struct flashctx *flash);
+int spi_byte_program_4ba(struct flashctx *flash, unsigned int addr, uint8_t databyte);
+int spi_nbyte_program_4ba(struct flashctx *flash, unsigned int addr, const uint8_t *bytes, unsigned int len);
+int spi_nbyte_read_4ba(struct flashctx *flash, unsigned int addr, uint8_t *bytes, unsigned int len);
+int spi_block_erase_20_4ba(struct flashctx *flash, unsigned int addr, unsigned int blocklen);
+int spi_block_erase_52_4ba(struct flashctx *flash, unsigned int addr, unsigned int blocklen);
+int spi_block_erase_d8_4ba(struct flashctx *flash, unsigned int addr, unsigned int blocklen);
+
 #endif /* !__CHIPDRIVERS_H__ */
diff --git a/flash.h b/flash.h
index 67c7d20..611450f 100644
--- a/flash.h
+++ b/flash.h
@@ -119,6 +119,9 @@
 #define FEATURE_WRSR_EITHER	(FEATURE_WRSR_EWSR | FEATURE_WRSR_WREN)
 #define FEATURE_OTP		(1 << 8)
 #define FEATURE_QPI		(1 << 9)
+/* Feature bits used for 4-bytes addressing mode */
+#define FEATURE_4BA_SUPPORT		(1 << 10)
+#define FEATURE_4BA_ONLY 		(1 << 11)
 
 enum test_state {
 	OK = 0,
diff --git a/spi4ba.c b/spi4ba.c
new file mode 100644
index 0000000..72df874
--- /dev/null
+++ b/spi4ba.c
@@ -0,0 +1,327 @@
+/*
+ * This file is part of the flashrom project.
+ *
+ * Copyright (C) 2014 Boris Baykov
+ *
+ * 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; version 2 of the License.
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+/*
+ * SPI chip driver functions for 4-bytes addressing
+ */
+
+#include <string.h>
+#include "flash.h"
+#include "chipdrivers.h"
+#include "spi.h"
+#include "programmer.h"
+#include "spi4ba.h"
+
+/* #define MSG_TRACE_4BA_FUNCS 1 */
+
+#ifdef MSG_TRACE_4BA_FUNCS
+#define msg_trace(...) print(MSG_DEBUG, __VA_ARGS__)
+#else
+#define msg_trace(...)
+#endif
+
+/* Enter 4-bytes addressing mode (without sending WREN before) */
+int spi_enter_4ba_b7(struct flashctx *flash)
+{
+	const unsigned char cmd[JEDEC_ENTER_4_BYTE_ADDR_MODE_OUTSIZE] = { JEDEC_ENTER_4_BYTE_ADDR_MODE };
+
+	msg_trace("-> %s\n", __func__);
+
+	/* Switch to 4-bytes addressing mode  */
+	return spi_send_command(flash, sizeof(cmd), 0, cmd, NULL);
+}
+
+/* Enter 4-bytes addressing mode with sending WREN before */
+int spi_enter_4ba_b7_we(struct flashctx *flash)
+{
+	int result;
+	struct spi_command cmds[] = {
+	{
+		.writecnt	= JEDEC_WREN_OUTSIZE,
+		.writearr	= (const unsigned char[]){ JEDEC_WREN },
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}, {
+		.writecnt	= JEDEC_ENTER_4_BYTE_ADDR_MODE_OUTSIZE,
+		.writearr	= (const unsigned char[]){ JEDEC_ENTER_4_BYTE_ADDR_MODE },
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}, {
+		.writecnt	= 0,
+		.writearr	= NULL,
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}};
+
+	msg_trace("-> %s\n", __func__);
+
+	/* Switch to 4-bytes addressing mode  */
+	result = spi_send_multicommand(flash, cmds);
+	if (result) {
+		msg_cerr("%s failed during command execution\n", __func__);
+	}
+	return result;
+}
+
+/* Program one flash byte from 4-bytes addressing mode */
+int spi_byte_program_4ba(struct flashctx *flash, unsigned int addr,
+				 uint8_t databyte)
+{
+	int result;
+	struct spi_command cmds[] = {
+	{
+		.writecnt	= JEDEC_WREN_OUTSIZE,
+		.writearr	= (const unsigned char[]){ JEDEC_WREN },
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}, {
+		.writecnt	= JEDEC_BYTE_PROGRAM_OUTSIZE + 1,
+		.writearr	= (const unsigned char[]){
+					JEDEC_BYTE_PROGRAM,
+					(addr >> 24) & 0xff,
+					(addr >> 16) & 0xff,
+					(addr >> 8) & 0xff,
+					(addr & 0xff),
+					databyte
+				},
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}, {
+		.writecnt	= 0,
+		.writearr	= NULL,
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}};
+
+	msg_trace("-> %s (0x%08X)\n", __func__, addr);
+
+	result = spi_send_multicommand(flash, cmds);
+	if (result) {
+		msg_cerr("%s failed during command execution at address 0x%x\n",
+			__func__, addr);
+	}
+	return result;
+}
+
+/* Program flash bytes from 4-bytes addressing mode */
+int spi_nbyte_program_4ba(struct flashctx *flash, unsigned int addr,
+			  const uint8_t *bytes, unsigned int len)
+{
+	int result;
+	unsigned char cmd[(JEDEC_BYTE_PROGRAM_OUTSIZE + 1) - 1 + 256] = {
+		JEDEC_BYTE_PROGRAM,
+		(addr >> 24) & 0xff,
+		(addr >> 16) & 0xff,
+		(addr >> 8) & 0xff,
+		(addr >> 0) & 0xff
+	};
+	struct spi_command cmds[] = {
+	{
+		.writecnt	= JEDEC_WREN_OUTSIZE,
+		.writearr	= (const unsigned char[]){ JEDEC_WREN },
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}, {
+		.writecnt	= (JEDEC_BYTE_PROGRAM_OUTSIZE + 1) - 1 + len,
+		.writearr	= cmd,
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}, {
+		.writecnt	= 0,
+		.writearr	= NULL,
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}};
+
+	msg_trace("-> %s (0x%08X-0x%08X)\n", __func__, addr, addr + len - 1);
+
+	if (!len) {
+		msg_cerr("%s called for zero-length write\n", __func__);
+		return 1;
+	}
+	if (len > 256) {
+		msg_cerr("%s called for too long a write\n", __func__);
+		return 1;
+	}
+
+	memcpy(&cmd[(JEDEC_BYTE_PROGRAM_OUTSIZE + 1) - 1], bytes, len);
+
+	result = spi_send_multicommand(flash, cmds);
+	if (result) {
+		msg_cerr("%s failed during command execution at address 0x%x\n",
+			__func__, addr);
+	}
+	return result;
+}
+
+/* Read flash bytes from 4-bytes addressing mode */
+int spi_nbyte_read_4ba(struct flashctx *flash, unsigned int addr,
+		   uint8_t *bytes, unsigned int len)
+{
+	const unsigned char cmd[JEDEC_READ_OUTSIZE + 1] = {
+		JEDEC_READ,
+		(addr >> 24) & 0xff,
+		(addr >> 16) & 0xff,
+		(addr >> 8) & 0xff,
+		(addr >> 0) & 0xff
+	};
+
+	msg_trace("-> %s (0x%08X-0x%08X)\n", __func__, addr, addr + len - 1);
+
+	/* Send Read */
+	return spi_send_command(flash, sizeof(cmd), len, cmd, bytes);
+}
+
+/* Erases 4 KB of flash from 4-bytes addressing mode */
+int spi_block_erase_20_4ba(struct flashctx *flash, unsigned int addr,
+		       unsigned int blocklen)
+{
+	int result;
+	struct spi_command cmds[] = {
+	{
+		.writecnt	= JEDEC_WREN_OUTSIZE,
+		.writearr	= (const unsigned char[]){ JEDEC_WREN },
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}, {
+		.writecnt	= JEDEC_SE_OUTSIZE + 1,
+		.writearr	= (const unsigned char[]){
+					JEDEC_SE,
+					(addr >> 24) & 0xff,
+					(addr >> 16) & 0xff,
+					(addr >> 8) & 0xff,
+					(addr & 0xff)
+				},
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}, {
+		.writecnt	= 0,
+		.writearr	= NULL,
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}};
+
+	msg_trace("-> %s (0x%08X-0x%08X)\n", __func__, addr, addr + blocklen - 1);
+
+	result = spi_send_multicommand(flash, cmds);
+	if (result) {
+		msg_cerr("%s failed during command execution at address 0x%x\n",
+			__func__, addr);
+		return result;
+	}
+	/* Wait until the Write-In-Progress bit is cleared.
+	 * This usually takes 15-800 ms, so wait in 10 ms steps.
+	 */
+	while (spi_read_status_register(flash) & SPI_SR_WIP)
+		programmer_delay(10 * 1000);
+	/* FIXME: Check the status register for errors. */
+	return 0;
+}
+
+/* Erases 32 KB of flash from 4-bytes addressing mode */
+int spi_block_erase_52_4ba(struct flashctx *flash, unsigned int addr,
+		       unsigned int blocklen)
+{
+	int result;
+	struct spi_command cmds[] = {
+	{
+		.writecnt	= JEDEC_WREN_OUTSIZE,
+		.writearr	= (const unsigned char[]){ JEDEC_WREN },
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}, {
+		.writecnt	= JEDEC_BE_52_OUTSIZE + 1,
+		.writearr	= (const unsigned char[]){
+					JEDEC_BE_52,
+					(addr >> 24) & 0xff,
+					(addr >> 16) & 0xff,
+					(addr >> 8) & 0xff,
+					(addr & 0xff)
+				},
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}, {
+		.writecnt	= 0,
+		.writearr	= NULL,
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}};
+
+	msg_trace("-> %s (0x%08X-0x%08X)\n", __func__, addr, addr + blocklen - 1);
+
+	result = spi_send_multicommand(flash, cmds);
+	if (result) {
+		msg_cerr("%s failed during command execution at address 0x%x\n",
+			__func__, addr);
+		return result;
+	}
+	/* Wait until the Write-In-Progress bit is cleared.
+	 * This usually takes 100-4000 ms, so wait in 100 ms steps.
+	 */
+	while (spi_read_status_register(flash) & SPI_SR_WIP)
+		programmer_delay(100 * 1000);
+	/* FIXME: Check the status register for errors. */
+	return 0;
+}
+
+/* Erases 64 KB of flash from 4-bytes addressing mode */
+int spi_block_erase_d8_4ba(struct flashctx *flash, unsigned int addr,
+		       unsigned int blocklen)
+{
+	int result;
+	struct spi_command cmds[] = {
+	{
+		.writecnt	= JEDEC_WREN_OUTSIZE,
+		.writearr	= (const unsigned char[]){ JEDEC_WREN },
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}, {
+		.writecnt	= JEDEC_BE_D8_OUTSIZE + 1,
+		.writearr	= (const unsigned char[]){
+					JEDEC_BE_D8,
+					(addr >> 24) & 0xff,
+					(addr >> 16) & 0xff,
+					(addr >> 8) & 0xff,
+					(addr & 0xff)
+				},
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}, {
+		.writecnt	= 0,
+		.writearr	= NULL,
+		.readcnt	= 0,
+		.readarr	= NULL,
+	}};
+
+	msg_trace("-> %s (0x%08X-0x%08X)\n", __func__, addr, addr + blocklen - 1);
+
+	result = spi_send_multicommand(flash, cmds);
+	if (result) {
+		msg_cerr("%s failed during command execution at address 0x%x\n",
+			__func__, addr);
+		return result;
+	}
+	/* Wait until the Write-In-Progress bit is cleared.
+	 * This usually takes 100-4000 ms, so wait in 100 ms steps.
+	 */
+	while (spi_read_status_register(flash) & SPI_SR_WIP)
+		programmer_delay(100 * 1000);
+	/* FIXME: Check the status register for errors. */
+	return 0;
+}
diff --git a/spi4ba.h b/spi4ba.h
new file mode 100644
index 0000000..15feecb
--- /dev/null
+++ b/spi4ba.h
@@ -0,0 +1,54 @@
+/*
+ * This file is part of the flashrom project.
+ *
+ * Copyright (C) 2014 Boris Baykov
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+*/
+
+/*
+ * JEDEC flash chips instructions for 4-bytes addressing
+ * SPI chip driver functions for 4-bytes addressing
+ */
+
+#ifndef __SPI_4BA_H__
+#define __SPI_4BA_H__ 1
+
+/* Enter 4-byte Address Mode */
+#define JEDEC_ENTER_4_BYTE_ADDR_MODE		0xB7
+#define JEDEC_ENTER_4_BYTE_ADDR_MODE_OUTSIZE	0x01
+#define JEDEC_ENTER_4_BYTE_ADDR_MODE_INSIZE	0x00
+
+/* Exit 4-byte Address Mode */
+#define JEDEC_EXIT_4_BYTE_ADDR_MODE		0xE9
+#define JEDEC_EXIT_4_BYTE_ADDR_MODE_OUTSIZE	0x01
+#define JEDEC_EXIT_4_BYTE_ADDR_MODE_INSIZE	0x00
+
+/* enter 4-bytes addressing mode */
+int spi_enter_4ba_b7(struct flashctx *flash);
+int spi_enter_4ba_b7_we(struct flashctx *flash);
+
+/* read/write flash bytes in 4-bytes addressing mode */
+int spi_byte_program_4ba(struct flashctx *flash, unsigned int addr, uint8_t databyte);
+int spi_nbyte_program_4ba(struct flashctx *flash, unsigned int addr, const uint8_t *bytes, unsigned int len);
+int spi_nbyte_read_4ba(struct flashctx *flash, unsigned int addr, uint8_t *bytes, unsigned int len);
+
+/* erase flash bytes in 4-bytes addressing mode */
+int spi_block_erase_20_4ba(struct flashctx *flash, unsigned int addr, unsigned int blocklen);
+int spi_block_erase_52_4ba(struct flashctx *flash, unsigned int addr, unsigned int blocklen);
+int spi_block_erase_d8_4ba(struct flashctx *flash, unsigned int addr, unsigned int blocklen);
+
+
+#endif /* __SPI_4BA_H__ */