diff --git a/arch/sandbox/cpu/os.c b/arch/sandbox/cpu/os.c
index 1c4aa3f..9b052ee 100644
--- a/arch/sandbox/cpu/os.c
+++ b/arch/sandbox/cpu/os.c
@@ -385,15 +385,15 @@ const char *os_dirent_get_typename(enum os_dirent_t type)
 	return os_dirent_typename[OS_FILET_UNKNOWN];
 }
 
-ssize_t os_get_filesize(const char *fname)
+int os_get_filesize(const char *fname, off_t *size)
 {
 	struct stat buf;
 	int ret;
 
 	ret = stat(fname, &buf);
-	if (ret)
-		return ret;
-	return buf.st_size;
+	if (ret == 0)
+		*size = buf.st_size;
+	return ret;
 }
 
 void os_putc(int ch)
@@ -427,10 +427,10 @@ int os_read_ram_buf(const char *fname)
 {
 	struct sandbox_state *state = state_get_current();
 	int fd, ret;
-	int size;
+	off_t size;
 
-	size = os_get_filesize(fname);
-	if (size < 0)
+	ret = os_get_filesize(fname, &size);
+	if (ret < 0)
 		return -ENOENT;
 	if (size != state->ram_size)
 		return -ENOSPC;
diff --git a/arch/sandbox/cpu/state.c b/arch/sandbox/cpu/state.c
index 59adad6..e0d119a 100644
--- a/arch/sandbox/cpu/state.c
+++ b/arch/sandbox/cpu/state.c
@@ -49,12 +49,12 @@ static int state_ensure_space(int extra_size)
 
 static int state_read_file(struct sandbox_state *state, const char *fname)
 {
-	int size;
+	off_t size;
 	int ret;
 	int fd;
 
-	size = os_get_filesize(fname);
-	if (size < 0) {
+	ret = os_get_filesize(fname, &size);
+	if (ret < 0) {
 		printf("Cannot find sandbox state file '%s'\n", fname);
 		return -ENOENT;
 	}
diff --git a/common/board_f.c b/common/board_f.c
index e6aa298..b8ec7ac 100644
--- a/common/board_f.c
+++ b/common/board_f.c
@@ -291,7 +291,7 @@ static int read_fdt_from_file(void)
 	struct sandbox_state *state = state_get_current();
 	const char *fname = state->fdt_fname;
 	void *blob;
-	ssize_t size;
+	off_t size;
 	int err;
 	int fd;
 
@@ -304,8 +304,8 @@ static int read_fdt_from_file(void)
 		return -EINVAL;
 	}
 
-	size = os_get_filesize(fname);
-	if (size < 0) {
+	err = os_get_filesize(fname, &size);
+	if (err < 0) {
 		printf("Failed to file FDT file '%s'\n", fname);
 		return -ENOENT;
 	}
diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c
index 33d69c9..fd9b611 100644
--- a/fs/ext4/ext4_common.c
+++ b/fs/ext4/ext4_common.c
@@ -2003,9 +2003,9 @@ int ext4fs_iterate_dir(struct ext2fs_node *dir, char *name,
 					printf("< ? > ");
 					break;
 				}
-				printf("%10d %s\n",
-					__le32_to_cpu(fdiro->inode.size),
-					filename);
+				printf("%10u %s\n",
+				       __le32_to_cpu(fdiro->inode.size),
+				       filename);
 			}
 			free(fdiro);
 		}
@@ -2169,11 +2169,10 @@ int ext4fs_find_file(const char *path, struct ext2fs_node *rootnode,
 	return 1;
 }
 
-int ext4fs_open(const char *filename)
+int ext4fs_open(const char *filename, off_t *len)
 {
 	struct ext2fs_node *fdiro = NULL;
 	int status;
-	int len;
 
 	if (ext4fs_root == NULL)
 		return -1;
@@ -2190,10 +2189,10 @@ int ext4fs_open(const char *filename)
 		if (status == 0)
 			goto fail;
 	}
-	len = __le32_to_cpu(fdiro->inode.size);
+	*len = __le32_to_cpu(fdiro->inode.size);
 	ext4fs_file = fdiro;
 
-	return len;
+	return 0;
 fail:
 	ext4fs_free_node(fdiro, &ext4fs_root->diropen);
 
diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c
index cbdc220..3e4eaaa 100644
--- a/fs/ext4/ext4fs.c
+++ b/fs/ext4/ext4fs.c
@@ -176,15 +176,19 @@ int ext4fs_ls(const char *dirname)
 
 int ext4fs_exists(const char *filename)
 {
-	int file_len;
+	off_t file_len;
+	int ret;
 
-	file_len = ext4fs_open(filename);
-	return file_len >= 0;
+	ret = ext4fs_open(filename, &file_len);
+	return ret == 0;
 }
 
-int ext4fs_size(const char *filename)
+int ext4fs_size(const char *filename, off_t *file_size)
 {
-	return ext4fs_open(filename);
+	int ret;
+
+	ret =  ext4fs_open(filename, file_size);
+	return ret == 0;
 }
 
 int ext4fs_read(char *buf, unsigned len)
@@ -210,7 +214,8 @@ int ext4fs_probe(block_dev_desc_t *fs_dev_desc,
 
 int ext4_read_file(const char *filename, void *buf, int offset, int len)
 {
-	int file_len;
+	off_t file_len;
+	int ret;
 	int len_read;
 
 	if (offset != 0) {
@@ -218,8 +223,8 @@ int ext4_read_file(const char *filename, void *buf, int offset, int len)
 		return -1;
 	}
 
-	file_len = ext4fs_open(filename);
-	if (file_len < 0) {
+	ret = ext4fs_open(filename, &file_len);
+	if (ret != 0) {
 		printf("** File not found %s **\n", filename);
 		return -1;
 	}
diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index 561921f..650ee7e 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -806,9 +806,9 @@ exit:
 __u8 do_fat_read_at_block[MAX_CLUSTSIZE]
 	__aligned(ARCH_DMA_MINALIGN);
 
-long
+int
 do_fat_read_at(const char *filename, unsigned long pos, void *buffer,
-	       unsigned long maxsize, int dols, int dogetsize)
+	       unsigned long maxsize, int dols, int dogetsize, off_t *size)
 {
 	char fnamecopy[2048];
 	boot_sector bs;
@@ -974,10 +974,10 @@ do_fat_read_at(const char *filename, unsigned long pos, void *buffer,
 						}
 						if (doit) {
 							if (dirc == ' ') {
-								printf(" %8ld   %s%c\n",
-									(long)FAT2CPU32(dentptr->size),
-									l_name,
-									dirc);
+								printf(" %8u   %s%c\n",
+								       FAT2CPU32(dentptr->size),
+								       l_name,
+								       dirc);
 							} else {
 								printf("            %s%c\n",
 									l_name,
@@ -1032,9 +1032,9 @@ do_fat_read_at(const char *filename, unsigned long pos, void *buffer,
 				}
 				if (doit) {
 					if (dirc == ' ') {
-						printf(" %8ld   %s%c\n",
-							(long)FAT2CPU32(dentptr->size),
-							s_name, dirc);
+						printf(" %8u   %s%c\n",
+						       FAT2CPU32(dentptr->size),
+						       s_name, dirc);
 					} else {
 						printf("            %s%c\n",
 							s_name, dirc);
@@ -1153,20 +1153,28 @@ rootdir_done:
 	}
 
 	if (dogetsize)
-		ret = FAT2CPU32(dentptr->size);
+		*size = FAT2CPU32(dentptr->size);
 	else
-		ret = get_contents(mydata, dentptr, pos, buffer, maxsize);
-	debug("Size: %d, got: %ld\n", FAT2CPU32(dentptr->size), ret);
+		*size = get_contents(mydata, dentptr, pos, buffer, maxsize);
+	debug("Size: %u, got: %u\n", FAT2CPU32(dentptr->size),
+	      (unsigned) *size);
 
 exit:
 	free(mydata->fatbuf);
 	return ret;
 }
 
-long
+int
 do_fat_read(const char *filename, void *buffer, unsigned long maxsize, int dols)
 {
-	return do_fat_read_at(filename, 0, buffer, maxsize, dols, 0);
+	int ret;
+	off_t size;
+
+	ret = do_fat_read_at(filename, 0, buffer, maxsize, dols, 0, &size);
+	if (ret == 0)
+		return size;
+	else
+		return ret;
 }
 
 int file_fat_detectfs(void)
@@ -1238,21 +1246,34 @@ int file_fat_ls(const char *dir)
 
 int fat_exists(const char *filename)
 {
-	int sz;
-	sz = do_fat_read_at(filename, 0, NULL, 0, LS_NO, 1);
-	return sz >= 0;
+	int ret;
+	off_t sz;
+
+	ret = do_fat_read_at(filename, 0, NULL, 0, LS_NO, 1, &sz);
+	return ret == 0;
 }
 
-int fat_size(const char *filename)
+int fat_size(const char *filename, off_t *sz)
 {
-	return do_fat_read_at(filename, 0, NULL, 0, LS_NO, 1);
+	int ret;
+
+	ret =  do_fat_read_at(filename, 0, NULL, 0, LS_NO, 1, sz);
+	return ret == 0;
 }
 
 long file_fat_read_at(const char *filename, unsigned long pos, void *buffer,
 		      unsigned long maxsize)
 {
+	int ret;
+	off_t sz;
+
 	printf("reading %s\n", filename);
-	return do_fat_read_at(filename, pos, buffer, maxsize, LS_NO, 0);
+	ret = do_fat_read_at(filename, pos, buffer, maxsize, LS_NO, 0, &sz);
+
+	if (ret == 0)
+		return sz;
+	else
+		return ret;
 }
 
 long file_fat_read(const char *filename, void *buffer, unsigned long maxsize)
diff --git a/fs/fs.c b/fs/fs.c
index dd680f3..c2d5b5f 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -46,7 +46,7 @@ static inline int fs_exists_unsupported(const char *filename)
 	return 0;
 }
 
-static inline int fs_size_unsupported(const char *filename)
+static inline int fs_size_unsupported(const char *filename, off_t *sz)
 {
 	return -1;
 }
@@ -82,7 +82,7 @@ struct fstype_info {
 		     disk_partition_t *fs_partition);
 	int (*ls)(const char *dirname);
 	int (*exists)(const char *filename);
-	int (*size)(const char *filename);
+	int (*size)(const char *filename, off_t *size);
 	int (*read)(const char *filename, void *buf, int offset, int len);
 	int (*write)(const char *filename, void *buf, int offset, int len);
 	void (*close)(void);
@@ -233,13 +233,13 @@ int fs_exists(const char *filename)
 	return ret;
 }
 
-int fs_size(const char *filename)
+int fs_size(const char *filename, off_t *size)
 {
 	int ret;
 
 	struct fstype_info *info = fs_get_info(fs_type);
 
-	ret = info->size(filename);
+	ret = info->size(filename, size);
 
 	fs_close();
 
@@ -292,7 +292,8 @@ int fs_write(const char *filename, ulong addr, int offset, int len)
 int do_size(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
 		int fstype)
 {
-	int size;
+	off_t size;
+	int ret;
 
 	if (argc != 4)
 		return CMD_RET_USAGE;
@@ -300,8 +301,8 @@ int do_size(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
 	if (fs_set_blk_dev(argv[1], argv[2], fstype))
 		return 1;
 
-	size = fs_size(argv[3]);
-	if (size < 0)
+	ret = fs_size(argv[3], &size);
+	if (ret < 0)
 		return CMD_RET_FAILURE;
 
 	setenv_hex("filesize", size);
diff --git a/fs/sandbox/sandboxfs.c b/fs/sandbox/sandboxfs.c
index ba6402c..a384cc7 100644
--- a/fs/sandbox/sandboxfs.c
+++ b/fs/sandbox/sandboxfs.c
@@ -27,8 +27,13 @@ long sandbox_fs_read_at(const char *filename, unsigned long pos,
 		os_close(fd);
 		return ret;
 	}
-	if (!maxsize)
-		maxsize = os_get_filesize(filename);
+	if (!maxsize) {
+		ret = os_get_filesize(filename, (off_t *)&maxsize);
+		if (ret < 0) {
+			os_close(fd);
+			return ret;
+		}
+	}
 	size = os_read(fd, buffer, maxsize);
 	os_close(fd);
 
@@ -74,15 +79,19 @@ int sandbox_fs_ls(const char *dirname)
 
 int sandbox_fs_exists(const char *filename)
 {
-	ssize_t sz;
+	off_t sz;
+	int ret;
 
-	sz = os_get_filesize(filename);
-	return sz >= 0;
+	ret = os_get_filesize(filename, &sz);
+	return ret == 0;
 }
 
-int sandbox_fs_size(const char *filename)
+int sandbox_fs_size(const char *filename, off_t *size)
 {
-	return os_get_filesize(filename);
+	int ret;
+
+	ret = os_get_filesize(filename, size);
+	return ret == 0;
 }
 
 void sandbox_fs_close(void)
diff --git a/include/ext4fs.h b/include/ext4fs.h
index 6c419f3..1f04973 100644
--- a/include/ext4fs.h
+++ b/include/ext4fs.h
@@ -129,14 +129,14 @@ int ext4fs_write(const char *fname, unsigned char *buffer,
 #endif
 
 struct ext_filesystem *get_fs(void);
-int ext4fs_open(const char *filename);
+int ext4fs_open(const char *filename, off_t *size);
 int ext4fs_read(char *buf, unsigned len);
 int ext4fs_mount(unsigned part_length);
 void ext4fs_close(void);
 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, off_t *len);
 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);
diff --git a/include/fat.h b/include/fat.h
index 20ca3f3..56aa3b7 100644
--- a/include/fat.h
+++ b/include/fat.h
@@ -198,7 +198,7 @@ int file_cd(const char *path);
 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, off_t *len);
 long file_fat_read_at(const char *filename, unsigned long pos, void *buffer,
 		      unsigned long maxsize);
 long file_fat_read(const char *filename, void *buffer, unsigned long maxsize);
diff --git a/include/fs.h b/include/fs.h
index 06a45f2..df39609 100644
--- a/include/fs.h
+++ b/include/fs.h
@@ -55,7 +55,7 @@ int fs_exists(const char *filename);
  *
  * Returns the file's size in bytes, or a negative value if it doesn't exist.
  */
-int fs_size(const char *filename);
+int fs_size(const char *filename, off_t *len);
 
 /*
  * Read file "filename" from the partition previously set by fs_set_blk_dev(),
diff --git a/include/os.h b/include/os.h
index 0230a7f..75d9846 100644
--- a/include/os.h
+++ b/include/os.h
@@ -219,7 +219,7 @@ const char *os_dirent_get_typename(enum os_dirent_t type);
  * @param fname		Filename to check
  * @return size of file, or -1 if an error ocurred
  */
-ssize_t os_get_filesize(const char *fname);
+int os_get_filesize(const char *fname, off_t *size);
 
 /**
  * Write a character to the controlling OS terminal
diff --git a/include/sandboxfs.h b/include/sandboxfs.h
index e7c3262..8588a29 100644
--- a/include/sandboxfs.h
+++ b/include/sandboxfs.h
@@ -26,7 +26,7 @@ long sandbox_fs_read_at(const char *filename, unsigned long pos,
 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 sandbox_fs_size(const char *filename, off_t *size);
 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);
 
