diff --git a/common/cmd_nand.c b/common/cmd_nand.c
index 7b1f830..f8fce0e 100644
--- a/common/cmd_nand.c
+++ b/common/cmd_nand.c
@@ -93,7 +93,7 @@
 }
 
 static int
-arg_off_size(int argc, char *argv[], nand_info_t *nand, ulong *off, ulong *size)
+arg_off_size(int argc, char *argv[], nand_info_t *nand, ulong *off, size_t *size)
 {
 	int idx = nand_curr_device;
 #if defined(CONFIG_CMD_JFFS2) && defined(CONFIG_JFFS2_CMDLINE)
@@ -136,7 +136,7 @@
 	}
 
 	if (argc >= 2) {
-		if (!(str2long(argv[1], size))) {
+		if (!(str2long(argv[1], (ulong *)size))) {
 			printf("'%s' is not a number\n", argv[1]);
 			return -1;
 		}
@@ -158,7 +158,8 @@
 int do_nand(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
 {
 	int i, dev, ret;
-	ulong addr, off, size;
+	ulong addr, off;
+	size_t size;
 	char *cmd, *s;
 	nand_info_t *nand;
 #ifdef CFG_NAND_QUIET
@@ -350,10 +351,10 @@
 		} else if (s != NULL && !strcmp(s, ".oob")) {
 			/* read out-of-band data */
 			if (read)
-				ret = nand->read_oob(nand, off, size, (size_t *) &size,
+				ret = nand->read_oob(nand, off, size, &size,
 						     (u_char *) addr);
 			else
-				ret = nand->write_oob(nand, off, size, (size_t *) &size,
+				ret = nand->write_oob(nand, off, size, &size,
 						      (u_char *) addr);
 		} else {
 			if (read)
@@ -481,7 +482,7 @@
 {
 	int r;
 	char *ep, *s;
-	ulong cnt;
+	size_t cnt;
 	image_header_t *hdr;
 	int jffs2 = 0;
 #if defined(CONFIG_FIT)
@@ -851,11 +852,11 @@
 				/* read out-of-band data */
 				if (cmd & NANDRW_READ) {
 					ret = nand_read_oob (nand_dev_desc + curr_device,
-							     off, size, (size_t *) & total,
+							     off, size, &total,
 							     (u_char *) addr);
 				} else {
 					ret = nand_write_oob (nand_dev_desc + curr_device,
-							      off, size, (size_t *) & total,
+							      off, size, &total,
 							      (u_char *) addr);
 				}
 				return ret;
@@ -891,7 +892,7 @@
 
 			ret = nand_legacy_rw (nand_dev_desc + curr_device,
 					      cmd, off, size,
-					      (size_t *) & total,
+					      &total,
 					      (u_char *) addr);
 
 			printf (" %d bytes %s: %s\n", total,
diff --git a/common/env_nand.c b/common/env_nand.c
index ce0a251..b6a5b4a 100644
--- a/common/env_nand.c
+++ b/common/env_nand.c
@@ -154,7 +154,7 @@
 #ifdef CFG_ENV_OFFSET_REDUND
 int saveenv(void)
 {
-	ulong total;
+	size_t total;
 	int ret = 0;
 
 	env_ptr->flags++;
diff --git a/include/nand.h b/include/nand.h
index 3c0752e..247d346 100644
--- a/include/nand.h
+++ b/include/nand.h
@@ -34,22 +34,22 @@
 extern nand_info_t nand_info[];
 extern void nand_init(void);
 
-static inline int nand_read(nand_info_t *info, ulong ofs, ulong *len, u_char *buf)
+static inline int nand_read(nand_info_t *info, off_t ofs, size_t *len, u_char *buf)
 {
 	return info->read(info, ofs, *len, (size_t *)len, buf);
 }
 
-static inline int nand_write(nand_info_t *info, ulong ofs, ulong *len, u_char *buf)
+static inline int nand_write(nand_info_t *info, off_t ofs, size_t *len, u_char *buf)
 {
 	return info->write(info, ofs, *len, (size_t *)len, buf);
 }
 
-static inline int nand_block_isbad(nand_info_t *info, ulong ofs)
+static inline int nand_block_isbad(nand_info_t *info, off_t ofs)
 {
 	return info->block_isbad(info, ofs);
 }
 
-static inline int nand_erase(nand_info_t *info, ulong off, ulong size)
+static inline int nand_erase(nand_info_t *info, off_t off, size_t size)
 {
 	struct erase_info instr;