diff --git a/lib/oofatfs/ff.c b/lib/oofatfs/ff.c
index 4e86805458..b0984756bf 100644
--- a/lib/oofatfs/ff.c
+++ b/lib/oofatfs/ff.c
@@ -2579,8 +2579,8 @@ FRESULT create_name (   /* FR_OK: successful, FR_INVALID_NAME: could not create
         if (w < 0x80 && chk_chr("\"*:<>\?|\x7F", w)) return FR_INVALID_NAME;    /* Reject illegal characters for LFN */
         lfn[di++] = w;                  /* Store the Unicode character */
     }
-    cf = ((w < ' ') || ((w == '/' || w == '\\') && p[si+1] < ' ')) ? NS_LAST : 0;   /* Set last segment flag if end of the path */
     *path = &p[si];                     /* Return pointer to the next segment */
+    cf = (w < ' ') ? NS_LAST : 0;       /* Set last segment flag if end of the path */
 #if _FS_RPATH != 0
     if ((di == 1 && lfn[di - 1] == '.') ||
         (di == 2 && lfn[di - 1] == '.' && lfn[di - 2] == '.')) {    /* Is this segment a dot name? */
diff --git a/shared-module/os/__init__.c b/shared-module/os/__init__.c
index a38f3781f1..313893d977 100644
--- a/shared-module/os/__init__.c
+++ b/shared-module/os/__init__.c
@@ -50,6 +50,20 @@ STATIC mp_vfs_mount_t *lookup_path(const char* path, mp_obj_t *path_out) {
     return vfs;
 }
 
+// Strip off trailing slashes to please underlying libraries
+STATIC mp_vfs_mount_t *lookup_dir_path(const char* path, mp_obj_t *path_out) {
+    const char *p_out;
+    mp_vfs_mount_t *vfs = mp_vfs_lookup_path(path, &p_out);
+    if (vfs != MP_VFS_NONE && vfs != MP_VFS_ROOT) {
+        size_t len = strlen(p_out);
+        while (len > 1 && p_out[len - 1] == '/') {
+            len--;
+        }
+        *path_out = mp_obj_new_str_of_type(&mp_type_str, (const byte*)p_out, len);
+    }
+    return vfs;
+}
+
 STATIC mp_obj_t mp_vfs_proxy_call(mp_vfs_mount_t *vfs, qstr meth_name, size_t n_args, const mp_obj_t *args) {
     if (vfs == MP_VFS_NONE) {
         // mount point not found
@@ -69,7 +83,7 @@ STATIC mp_obj_t mp_vfs_proxy_call(mp_vfs_mount_t *vfs, qstr meth_name, size_t n_
 
 void common_hal_os_chdir(const char* path) {
     mp_obj_t path_out;
-    mp_vfs_mount_t *vfs = lookup_path(path, &path_out);
+    mp_vfs_mount_t *vfs = lookup_dir_path(path, &path_out);
     MP_STATE_VM(vfs_cur) = vfs;
     if (vfs == MP_VFS_ROOT) {
         // If we change to the root dir and a VFS is mounted at the root then
@@ -93,7 +107,7 @@ mp_obj_t common_hal_os_getcwd(void) {
 
 mp_obj_t common_hal_os_listdir(const char* path) {
     mp_obj_t path_out;
-    mp_vfs_mount_t *vfs = lookup_path(path, &path_out);
+    mp_vfs_mount_t *vfs = lookup_dir_path(path, &path_out);
 
     mp_vfs_ilistdir_it_t iter;
     mp_obj_t iter_obj = MP_OBJ_FROM_PTR(&iter);
@@ -120,7 +134,7 @@ mp_obj_t common_hal_os_listdir(const char* path) {
 
 void common_hal_os_mkdir(const char* path) {
     mp_obj_t path_out;
-    mp_vfs_mount_t *vfs = lookup_path(path, &path_out);
+    mp_vfs_mount_t *vfs = lookup_dir_path(path, &path_out);
     if (vfs == MP_VFS_ROOT || (vfs != MP_VFS_NONE && !strcmp(mp_obj_str_get_str(path_out), "/"))) {
         mp_raise_OSError(MP_EEXIST);
     }
@@ -146,7 +160,7 @@ void common_hal_os_rename(const char* old_path, const char* new_path) {
 
 void common_hal_os_rmdir(const char* path) {
     mp_obj_t path_out;
-    mp_vfs_mount_t *vfs = lookup_path(path, &path_out);
+    mp_vfs_mount_t *vfs = lookup_dir_path(path, &path_out);
     mp_vfs_proxy_call(vfs, MP_QSTR_rmdir, 1, &path_out);
 }