diff --git a/unix/modffi.c b/unix/modffi.c
index 74194e2cc..7a35d61ef 100644
--- a/unix/modffi.c
+++ b/unix/modffi.c
@@ -126,8 +126,7 @@ STATIC ffi_type *char2ffi_type(char c)
 STATIC ffi_type *get_ffi_type(mp_obj_t o_in)
 {
     if (MP_OBJ_IS_STR(o_in)) {
-        mp_uint_t len;
-        const char *s = mp_obj_str_get_data(o_in, &len);
+        const char *s = mp_obj_str_get_str(o_in);
         ffi_type *t = char2ffi_type(*s);
         if (t != NULL) {
             return t;
diff --git a/unix/modos.c b/unix/modos.c
index d6e6a8fb3..8e746c163 100644
--- a/unix/modos.c
+++ b/unix/modos.c
@@ -46,8 +46,7 @@
 
 STATIC mp_obj_t mod_os_stat(mp_obj_t path_in) {
     struct stat sb;
-    mp_uint_t len;
-    const char *path = mp_obj_str_get_data(path_in, &len);
+    const char *path = mp_obj_str_get_str(path_in);
 
     int res = stat(path, &sb);
     RAISE_ERRNO(res, errno);
@@ -87,8 +86,7 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_os_stat_obj, mod_os_stat);
 
 STATIC mp_obj_t mod_os_statvfs(mp_obj_t path_in) {
     STRUCT_STATVFS sb;
-    mp_uint_t len;
-    const char *path = mp_obj_str_get_data(path_in, &len);
+    const char *path = mp_obj_str_get_str(path_in);
 
     int res = STATVFS(path, &sb);
     RAISE_ERRNO(res, errno);
@@ -110,8 +108,7 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_os_statvfs_obj, mod_os_statvfs);
 #endif
 
 STATIC mp_obj_t mod_os_unlink(mp_obj_t path_in) {
-    mp_uint_t len;
-    const char *path = mp_obj_str_get_data(path_in, &len);
+    const char *path = mp_obj_str_get_str(path_in);
 
     int r = unlink(path);
 
diff --git a/unix/modtermios.c b/unix/modtermios.c
index 2cb5f26df..5e82e772a 100644
--- a/unix/modtermios.c
+++ b/unix/modtermios.c
@@ -90,8 +90,7 @@ STATIC mp_obj_t mod_termios_tcsetattr(mp_obj_t fd_in, mp_obj_t when_in, mp_obj_t
         if (i == VMIN || i == VTIME) {
             term.c_cc[i] = mp_obj_get_int(cc->items[i]);
         } else {
-            mp_uint_t len;
-            term.c_cc[i] = *mp_obj_str_get_data(cc->items[i], &len);
+            term.c_cc[i] = *mp_obj_str_get_str(cc->items[i]);
         }
     }