diff --git a/board/gdsys/p1022/controlcenterd-id.c b/board/gdsys/p1022/controlcenterd-id.c
index 317669b..11d075c 100644
--- a/board/gdsys/p1022/controlcenterd-id.c
+++ b/board/gdsys/p1022/controlcenterd-id.c
@@ -932,11 +932,12 @@
 	struct key_program header;
 	uint32_t crc;
 	uint8_t buf[12];
-	int i;
+	loff_t i;
 
 	if (fs_set_blk_dev(ifname, dev_part_str, fs_type))
 		goto failure;
-	i = fs_read(path, (ulong)buf, 0, 12);
+	if (fs_read(path, (ulong)buf, 0, 12, &i) < 0)
+		goto failure;
 	if (i < 12)
 		goto failure;
 	header.magic = get_unaligned_be32(buf);
@@ -951,8 +952,9 @@
 		goto failure;
 	if (fs_set_blk_dev(ifname, dev_part_str, fs_type))
 		goto failure;
-	i = fs_read(path, (ulong)result, 0,
-		sizeof(struct key_program) + header.code_size);
+	if (fs_read(path, (ulong)result, 0,
+		    sizeof(struct key_program) + header.code_size, &i) < 0)
+		goto failure;
 	if (i <= 0)
 		goto failure;
 	*result = header;
@@ -1043,7 +1045,7 @@
 	const char *image_path = "/ccdm.itb";
 	char *mac_path = NULL;
 	ulong image_addr;
-	size_t image_size;
+	loff_t image_size;
 	uint32_t err;
 
 	printf("CCDM S2\n");
@@ -1085,10 +1087,11 @@
 	image_addr = (ulong)get_image_location();
 	if (fs_set_blk_dev("mmc", mmcdev, FS_TYPE_EXT))
 		goto failure;
-	image_size = fs_read(image_path, image_addr, 0, 0);
+	if (fs_read(image_path, image_addr, 0, 0, &image_size) < 0)
+		goto failure;
 	if (image_size <= 0)
 		goto failure;
-	printf("CCDM image found on %s, %d bytes\n", mmcdev, image_size);
+	printf("CCDM image found on %s, %lld bytes\n", mmcdev, image_size);
 
 	hmac_blob = load_key_chunk("mmc", mmcdev, FS_TYPE_EXT, mac_path);
 	if (!hmac_blob) {
diff --git a/common/cmd_fs.c b/common/cmd_fs.c
index 6754340..0d9da11 100644
--- a/common/cmd_fs.c
+++ b/common/cmd_fs.c
@@ -51,6 +51,23 @@
 	"      If 'pos' is 0 or omitted, the file is read from the start."
 )
 
+static int do_save_wrapper(cmd_tbl_t *cmdtp, int flag, int argc,
+				char * const argv[])
+{
+	return do_save(cmdtp, flag, argc, argv, FS_TYPE_ANY);
+}
+
+U_BOOT_CMD(
+	save,	7,	0,	do_save_wrapper,
+	"save file to a filesystem",
+	"<interface> <dev[:part]> <addr> <filename> bytes [pos]\n"
+	"    - Save binary file 'filename' to partition 'part' on device\n"
+	"      type 'interface' instance 'dev' from addr 'addr' in memory.\n"
+	"      'bytes' gives the size to save in bytes and is mandatory.\n"
+	"      'pos' gives the file byte position to start writing to.\n"
+	"      If 'pos' is 0 or omitted, the file is written from the start."
+)
+
 static int do_ls_wrapper(cmd_tbl_t *cmdtp, int flag, int argc,
 				char * const argv[])
 {
diff --git a/drivers/fpga/zynqpl.c b/drivers/fpga/zynqpl.c
index 68fe0f3..6a74f89 100644
--- a/drivers/fpga/zynqpl.c
+++ b/drivers/fpga/zynqpl.c
@@ -406,8 +406,8 @@
 	unsigned long ts; /* Timestamp */
 	u32 isr_status, swap;
 	u32 partialbit = 0;
-	u32 blocksize;
-	u32 pos = 0;
+	loff_t blocksize, actread;
+	loff_t pos = 0;
 	int fstype;
 	char *interface, *dev_part, *filename;
 
@@ -420,7 +420,7 @@
 	if (fs_set_blk_dev(interface, dev_part, fstype))
 		return FPGA_FAIL;
 
-	if (fs_read(filename, (u32) buf, pos, blocksize) < 0)
+	if (fs_read(filename, (u32) buf, pos, blocksize, &actread) < 0)
 		return FPGA_FAIL;
 
 	if (zynq_validate_bitstream(desc, buf, bsize, blocksize, &swap,
@@ -443,10 +443,10 @@
 			return FPGA_FAIL;
 
 		if (bsize > blocksize) {
-			if (fs_read(filename, (u32) buf, pos, blocksize) < 0)
+			if (fs_read(filename, (u32) buf, pos, blocksize, &actread) < 0)
 				return FPGA_FAIL;
 		} else {
-			if (fs_read(filename, (u32) buf, pos, bsize) < 0)
+			if (fs_read(filename, (u32) buf, pos, bsize, &actread) < 0)
 				return FPGA_FAIL;
 		}
 	} while (bsize > blocksize);
diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c
index d82266f..943b5bc 100644
--- a/fs/ext4/ext4fs.c
+++ b/fs/ext4/ext4fs.c
@@ -184,16 +184,9 @@
 	return ret == 0;
 }
 
-int ext4fs_size(const char *filename)
+int ext4fs_size(const char *filename, loff_t *size)
 {
-	loff_t	size;
-	int ret;
-
-	ret = ext4fs_open(filename, &size);
-	if (ret)
-		return ret;
-	else
-		return size;
+	return ext4fs_open(filename, size);
 }
 
 int ext4fs_read(char *buf, loff_t len, loff_t *actread)
@@ -217,10 +210,10 @@
 	return 0;
 }
 
-int ext4_read_file(const char *filename, void *buf, int offset, int len)
+int ext4_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
+		   loff_t *len_read)
 {
 	loff_t file_len;
-	loff_t len_read;
 	int ret;
 
 	if (offset != 0) {
@@ -237,12 +230,7 @@
 	if (len == 0)
 		len = file_len;
 
-	ret = ext4fs_read(buf, len, &len_read);
-
-	if (ret)
-		return ret;
-	else
-		return len_read;
+	return ext4fs_read(buf, len, len_read);
 }
 
 int ext4fs_uuid(char *uuid_str)
diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index 83d9ce7..04a51db 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -1248,16 +1248,9 @@
 	return ret == 0;
 }
 
-int fat_size(const char *filename)
+int fat_size(const char *filename, loff_t *size)
 {
-	loff_t size;
-	int ret;
-
-	ret = do_fat_read_at(filename, 0, NULL, 0, LS_NO, 1, &size);
-	if (ret)
-		return ret;
-	else
-		return size;
+	return do_fat_read_at(filename, 0, NULL, 0, LS_NO, 1, size);
 }
 
 int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
@@ -1280,18 +1273,16 @@
 		return actread;
 }
 
-int fat_read_file(const char *filename, void *buf, int offset, int len)
+int fat_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
+		  loff_t *actread)
 {
 	int ret;
-	loff_t actread;
 
-	ret = file_fat_read_at(filename, offset, buf, len, &actread);
-	if (ret) {
+	ret = file_fat_read_at(filename, offset, buf, len, actread);
+	if (ret)
 		printf("** Unable to read file %s **\n", filename);
-		return ret;
-	}
 
-	return actread;
+	return ret;
 }
 
 void fat_close(void)
diff --git a/fs/fs.c b/fs/fs.c
index e4ad6bc..3da7860 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -47,19 +47,21 @@
 	return 0;
 }
 
-static inline int fs_size_unsupported(const char *filename)
+static inline int fs_size_unsupported(const char *filename, loff_t *size)
 {
 	return -1;
 }
 
 static inline int fs_read_unsupported(const char *filename, void *buf,
-				      int offset, int len)
+				      loff_t offset, loff_t len,
+				      loff_t *actread)
 {
 	return -1;
 }
 
 static inline int fs_write_unsupported(const char *filename, void *buf,
-				      int offset, int len)
+				      loff_t offset, loff_t len,
+				      loff_t *actwrite)
 {
 	return -1;
 }
@@ -88,9 +90,11 @@
 		     disk_partition_t *fs_partition);
 	int (*ls)(const char *dirname);
 	int (*exists)(const char *filename);
-	int (*size)(const char *filename);
-	int (*read)(const char *filename, void *buf, int offset, int len);
-	int (*write)(const char *filename, void *buf, int offset, int len);
+	int (*size)(const char *filename, loff_t *size);
+	int (*read)(const char *filename, void *buf, loff_t offset,
+		    loff_t len, loff_t *actread);
+	int (*write)(const char *filename, void *buf, loff_t offset,
+		     loff_t len, loff_t *actwrite);
 	void (*close)(void);
 	int (*uuid)(char *uuid_str);
 };
@@ -106,7 +110,11 @@
 		.exists = fat_exists,
 		.size = fat_size,
 		.read = fat_read_file,
+#ifdef CONFIG_FAT_WRITE
+		.write = file_fat_write,
+#else
 		.write = fs_write_unsupported,
+#endif
 		.uuid = fs_uuid_unsupported,
 	},
 #endif
@@ -120,7 +128,11 @@
 		.exists = ext4fs_exists,
 		.size = ext4fs_size,
 		.read = ext4_read_file,
+#ifdef CONFIG_CMD_EXT4_WRITE
+		.write = ext4_write_file,
+#else
 		.write = fs_write_unsupported,
+#endif
 		.uuid = ext4fs_uuid,
 	},
 #endif
@@ -251,20 +263,21 @@
 	return ret;
 }
 
-int fs_size(const char *filename)
+int fs_size(const char *filename, loff_t *size)
 {
 	int ret;
 
 	struct fstype_info *info = fs_get_info(fs_type);
 
-	ret = info->size(filename);
+	ret = info->size(filename, size);
 
 	fs_close();
 
 	return ret;
 }
 
-int fs_read(const char *filename, ulong addr, int offset, int len)
+int fs_read(const char *filename, ulong addr, loff_t offset, loff_t len,
+	    loff_t *actread)
 {
 	struct fstype_info *info = fs_get_info(fs_type);
 	void *buf;
@@ -275,11 +288,11 @@
 	 * means read the whole file.
 	 */
 	buf = map_sysmem(addr, len);
-	ret = info->read(filename, buf, offset, len);
+	ret = info->read(filename, buf, offset, len, actread);
 	unmap_sysmem(buf);
 
 	/* If we requested a specific number of bytes, check we got it */
-	if (ret >= 0 && len && ret != len) {
+	if (ret == 0 && len && *actread != len) {
 		printf("** Unable to read file %s **\n", filename);
 		ret = -1;
 	}
@@ -288,17 +301,18 @@
 	return ret;
 }
 
-int fs_write(const char *filename, ulong addr, int offset, int len)
+int fs_write(const char *filename, ulong addr, loff_t offset, loff_t len,
+	     loff_t *actwrite)
 {
 	struct fstype_info *info = fs_get_info(fs_type);
 	void *buf;
 	int ret;
 
 	buf = map_sysmem(addr, len);
-	ret = info->write(filename, buf, offset, len);
+	ret = info->write(filename, buf, offset, len, actwrite);
 	unmap_sysmem(buf);
 
-	if (ret >= 0 && ret != len) {
+	if (ret < 0 && len != *actwrite) {
 		printf("** Unable to write file %s **\n", filename);
 		ret = -1;
 	}
@@ -310,7 +324,7 @@
 int do_size(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
 		int fstype)
 {
-	int size;
+	loff_t size;
 
 	if (argc != 4)
 		return CMD_RET_USAGE;
@@ -318,8 +332,7 @@
 	if (fs_set_blk_dev(argv[1], argv[2], fstype))
 		return 1;
 
-	size = fs_size(argv[3]);
-	if (size < 0)
+	if (fs_size(argv[3], &size) < 0)
 		return CMD_RET_FAILURE;
 
 	setenv_hex("filesize", size);
@@ -333,9 +346,10 @@
 	unsigned long addr;
 	const char *addr_str;
 	const char *filename;
-	unsigned long bytes;
-	unsigned long pos;
-	int len_read;
+	loff_t bytes;
+	loff_t pos;
+	loff_t len_read;
+	int ret;
 	unsigned long time;
 	char *ep;
 
@@ -377,12 +391,12 @@
 		pos = 0;
 
 	time = get_timer(0);
-	len_read = fs_read(filename, addr, pos, bytes);
+	ret = fs_read(filename, addr, pos, bytes, &len_read);
 	time = get_timer(time);
-	if (len_read <= 0)
+	if (ret < 0)
 		return 1;
 
-	printf("%d bytes read in %lu ms", len_read, time);
+	printf("%llu bytes read in %lu ms", len_read, time);
 	if (time > 0) {
 		puts(" (");
 		print_size(len_read / time * 1000, "/s");
@@ -426,9 +440,10 @@
 {
 	unsigned long addr;
 	const char *filename;
-	unsigned long bytes;
-	unsigned long pos;
-	int len;
+	loff_t bytes;
+	loff_t pos;
+	loff_t len;
+	int ret;
 	unsigned long time;
 
 	if (argc < 6 || argc > 7)
@@ -437,8 +452,8 @@
 	if (fs_set_blk_dev(argv[1], argv[2], fstype))
 		return 1;
 
-	filename = argv[3];
-	addr = simple_strtoul(argv[4], NULL, 16);
+	addr = simple_strtoul(argv[3], NULL, 16);
+	filename = argv[4];
 	bytes = simple_strtoul(argv[5], NULL, 16);
 	if (argc >= 7)
 		pos = simple_strtoul(argv[6], NULL, 16);
@@ -446,12 +461,12 @@
 		pos = 0;
 
 	time = get_timer(0);
-	len = fs_write(filename, addr, pos, bytes);
+	ret = fs_write(filename, addr, pos, bytes, &len);
 	time = get_timer(time);
-	if (len <= 0)
+	if (ret < 0)
 		return 1;
 
-	printf("%d bytes written in %lu ms", len, time);
+	printf("%llu bytes written in %lu ms", len, time);
 	if (time > 0) {
 		puts(" (");
 		print_size(len / time * 1000, "/s");
diff --git a/fs/sandbox/sandboxfs.c b/fs/sandbox/sandboxfs.c
index d11c087..a920bc0 100644
--- a/fs/sandbox/sandboxfs.c
+++ b/fs/sandbox/sandboxfs.c
@@ -103,46 +103,35 @@
 	return ret == 0;
 }
 
-int sandbox_fs_size(const char *filename)
+int sandbox_fs_size(const char *filename, loff_t *size)
 {
-	loff_t size;
-	int ret;
-
-	ret = os_get_filesize(filename, &size);
-	if (ret)
-		return ret;
-	else
-		return size;
+	return os_get_filesize(filename, size);
 }
 
 void sandbox_fs_close(void)
 {
 }
 
-int fs_read_sandbox(const char *filename, void *buf, int offset, int len)
+int fs_read_sandbox(const char *filename, void *buf, loff_t offset, loff_t len,
+		    loff_t *actread)
 {
 	int ret;
-	loff_t actread;
 
-	ret = sandbox_fs_read_at(filename, offset, buf, len, &actread);
-	if (ret) {
+	ret = sandbox_fs_read_at(filename, offset, buf, len, actread);
+	if (ret)
 		printf("** Unable to read file %s **\n", filename);
-		return ret;
-	}
 
-	return actread;
+	return ret;
 }
 
-int fs_write_sandbox(const char *filename, void *buf, int offset, int len)
+int fs_write_sandbox(const char *filename, void *buf, loff_t offset,
+		     loff_t len, loff_t *actwrite)
 {
 	int ret;
-	loff_t actwrite;
 
-	ret = sandbox_fs_write_at(filename, offset, buf, len, &actwrite);
-	if (ret) {
+	ret = sandbox_fs_write_at(filename, offset, buf, len, actwrite);
+	if (ret)
 		printf("** Unable to write file %s **\n", filename);
-		return ret;
-	}
 
-	return actwrite;
+	return ret;
 }
diff --git a/include/ext4fs.h b/include/ext4fs.h
index 5c524a6..6888adc 100644
--- a/include/ext4fs.h
+++ b/include/ext4fs.h
@@ -138,14 +138,15 @@
 void ext4fs_reinit_global(void);
 int ext4fs_ls(const char *dirname);
 int ext4fs_exists(const char *filename);
-int ext4fs_size(const char *filename);
+int ext4fs_size(const char *filename, loff_t *size);
 void ext4fs_free_node(struct ext2fs_node *node, struct ext2fs_node *currroot);
 int ext4fs_devread(lbaint_t sector, int byte_offset, int byte_len, char *buf);
 void ext4fs_set_blk_dev(block_dev_desc_t *rbdd, disk_partition_t *info);
 long int read_allocated_block(struct ext2_inode *inode, int fileblock);
 int ext4fs_probe(block_dev_desc_t *fs_dev_desc,
 		 disk_partition_t *fs_partition);
-int ext4_read_file(const char *filename, void *buf, int offset, int len);
+int ext4_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
+		   loff_t *actread);
 int ext4_read_superblock(char *buffer);
 int ext4fs_uuid(char *uuid_str);
 #endif
diff --git a/include/fat.h b/include/fat.h
index 99c6429..3038bd7 100644
--- a/include/fat.h
+++ b/include/fat.h
@@ -198,7 +198,7 @@
 int file_fat_detectfs(void);
 int file_fat_ls(const char *dir);
 int fat_exists(const char *filename);
-int fat_size(const char *filename);
+int fat_size(const char *filename, loff_t *size);
 int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
 		     loff_t maxsize, loff_t *actread);
 int file_fat_read(const char *filename, void *buffer, int maxsize);
@@ -208,6 +208,7 @@
 
 int file_fat_write(const char *filename, void *buf, loff_t offset, loff_t len,
 		   loff_t *actwrite);
-int fat_read_file(const char *filename, void *buf, int offset, int len);
+int fat_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
+		  loff_t *actread);
 void fat_close(void);
 #endif /* _FAT_H_ */
diff --git a/include/fs.h b/include/fs.h
index 491c60a..ffb6ce7 100644
--- a/include/fs.h
+++ b/include/fs.h
@@ -51,32 +51,41 @@
 int fs_exists(const char *filename);
 
 /*
- * Determine a file's size
+ * fs_size - Determine a file's size
  *
- * Returns the file's size in bytes, or a negative value if it doesn't exist.
+ * @filename: Name of the file
+ * @size: Size of file
+ * @return 0 if ok with valid *size, negative on error
  */
-int fs_size(const char *filename);
+int fs_size(const char *filename, loff_t *size);
 
 /*
- * Read file "filename" from the partition previously set by fs_set_blk_dev(),
- * to address "addr", starting at byte offset "offset", and reading "len"
- * bytes. "offset" may be 0 to read from the start of the file. "len" may be
- * 0 to read the entire file. Note that not all filesystem types support
- * either/both offset!=0 or len!=0.
+ * fs_read - Read file from the partition previously set by fs_set_blk_dev()
+ * Note that not all filesystem types support either/both offset!=0 or len!=0.
  *
- * Returns number of bytes read on success. Returns <= 0 on error.
+ * @filename: Name of file to read from
+ * @addr: The address to read into
+ * @offset: The offset in file to read from
+ * @len: The number of bytes to read. Maybe 0 to read entire file
+ * @actread: Returns the actual number of bytes read
+ * @return 0 if ok with valid *actread, -1 on error conditions
  */
-int fs_read(const char *filename, ulong addr, int offset, int len);
+int fs_read(const char *filename, ulong addr, loff_t offset, loff_t len,
+	    loff_t *actread);
 
 /*
- * Write file "filename" to the partition previously set by fs_set_blk_dev(),
- * from address "addr", starting at byte offset "offset", and writing "len"
- * bytes. "offset" may be 0 to write to the start of the file. Note that not
- * all filesystem types support offset!=0.
+ * fs_write - Write file to the partition previously set by fs_set_blk_dev()
+ * Note that not all filesystem types support offset!=0.
  *
- * Returns number of bytes read on success. Returns <= 0 on error.
+ * @filename: Name of file to read from
+ * @addr: The address to read into
+ * @offset: The offset in file to read from. Maybe 0 to write to start of file
+ * @len: The number of bytes to write
+ * @actwrite: Returns the actual number of bytes written
+ * @return 0 if ok with valid *actwrite, -1 on error conditions
  */
-int fs_write(const char *filename, ulong addr, int offset, int len);
+int fs_write(const char *filename, ulong addr, loff_t offset, loff_t len,
+	     loff_t *actwrite);
 
 /*
  * Common implementation for various filesystem commands, optionally limited
diff --git a/include/sandboxfs.h b/include/sandboxfs.h
index 8e5da6b..4c7745d 100644
--- a/include/sandboxfs.h
+++ b/include/sandboxfs.h
@@ -28,8 +28,10 @@
 void sandbox_fs_close(void);
 int sandbox_fs_ls(const char *dirname);
 int sandbox_fs_exists(const char *filename);
-int sandbox_fs_size(const char *filename);
-int fs_read_sandbox(const char *filename, void *buf, int offset, int len);
-int fs_write_sandbox(const char *filename, void *buf, int offset, int len);
+int sandbox_fs_size(const char *filename, loff_t *size);
+int fs_read_sandbox(const char *filename, void *buf, loff_t offset, loff_t len,
+		    loff_t *actread);
+int fs_write_sandbox(const char *filename, void *buf, loff_t offset,
+		     loff_t len, loff_t *actwrite);
 
 #endif