diff --git a/include/fs/fs.h b/include/fs/fs.h
index 2758f325f9a4..0ed06922a1b8 100644
--- a/include/fs/fs.h
+++ b/include/fs/fs.h
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2016 Intel Corporation.
- * Copyright (c) 2020 Nordic Semiconductor ASA
+ * Copyright (c) 2020-2021 Nordic Semiconductor ASA
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -8,24 +8,7 @@
 #ifndef ZEPHYR_INCLUDE_FS_FS_H_
 #define ZEPHYR_INCLUDE_FS_FS_H_
 
-#ifdef CONFIG_ARCH_POSIX
-#ifndef __ssize_t_defined
-typedef __SIZE_TYPE__ ssize_t;
-#define __ssize_t_defined
-#endif
-
-#ifndef __off_t_defined
-#ifndef __USE_FILE_OFFSET64
-typedef long int off_t;
-#else
-typedef long long int off_t;
-#endif
-#define __off_t_defined
-#endif
-
-#else
 #include <sys/types.h>
-#endif
 
 #include <sys/dlist.h>
 #include <fs/fs_interface.h>
diff --git a/samples/subsys/fs/littlefs/src/main.c b/samples/subsys/fs/littlefs/src/main.c
index c6a9e3842a3a..63838080e8aa 100644
--- a/samples/subsys/fs/littlefs/src/main.c
+++ b/samples/subsys/fs/littlefs/src/main.c
@@ -14,6 +14,16 @@
 #include <fs/littlefs.h>
 #include <storage/flash_map.h>
 
+/*
+ * FIXME: The Zephyr always overrides uintptr_t as long int, which causes type size mismatch with
+ * 32bit tools that may define PRIuPTR as "u".
+ * See: include/toolchain/zephyr_stdint.h.
+ * The UINTPTR_T_CAST should be replaced with cast to uintptr_t when this thing gets fixed.
+ */
+#undef PRIuPTR
+#define PRIuPTR		"lu"
+#define UINTPTR_T_CAST(t)	((unsigned long)(t))
+
 /* Matches LFS_NAME_MAX */
 #define MAX_PATH_LEN 255
 
@@ -73,8 +83,8 @@ void main(void)
 	!(FSTAB_ENTRY_DT_MOUNT_FLAGS(PARTITION_NODE) & FS_MOUNT_FLAG_AUTOMOUNT)
 	rc = fs_mount(mp);
 	if (rc < 0) {
-		printk("FAIL: mount id %u at %s: %d\n",
-		       (unsigned int)mp->storage_dev, mp->mnt_point,
+		printk("FAIL: mount id %" PRIuPTR " at %s: %d\n",
+		       UINTPTR_T_CAST(mp->storage_dev), mp->mnt_point,
 		       rc);
 		return;
 	}
@@ -100,7 +110,7 @@ void main(void)
 	rc = fs_stat(fname, &dirent);
 	printk("%s stat: %d\n", fname, rc);
 	if (rc >= 0) {
-		printk("\tfn '%s' siz %u\n", dirent.name, dirent.size);
+		printk("\tfn '%s' size %zu\n", dirent.name, dirent.size);
 	}
 
 	struct fs_file_t file;
@@ -149,7 +159,7 @@ void main(void)
 			printk("End of files\n");
 			break;
 		}
-		printk("  %c %u %s\n",
+		printk("  %c %zu %s\n",
 		       (ent.type == FS_DIR_ENTRY_FILE) ? 'F' : 'D',
 		       ent.size,
 		       ent.name);