diff --git a/include/coreinit/filesystem.h b/include/coreinit/filesystem.h
index 4f303021..ba2491b0 100644
--- a/include/coreinit/filesystem.h
+++ b/include/coreinit/filesystem.h
@@ -472,6 +472,7 @@ FSChangeMode(FSClient *client,
              FSCmdBlock *block,
              char *path,
              FSMode mode,
+             FSMode modeMask,
              FSErrorFlag errorMask);
 
 FSStatus
@@ -479,6 +480,7 @@ FSChangeModeAsync(FSClient *client,
                   FSCmdBlock *block,
                   char *path,
                   FSMode mode,
+                  FSMode modeMask,
                   FSErrorFlag errorMask,
                   FSAsyncData *asyncData);
 
diff --git a/libraries/wutdevoptab/devoptab_fs_chmod.c b/libraries/wutdevoptab/devoptab_fs_chmod.c
index 43a26920..bc4de68a 100644
--- a/libraries/wutdevoptab/devoptab_fs_chmod.c
+++ b/libraries/wutdevoptab/devoptab_fs_chmod.c
@@ -1,5 +1,13 @@
+#include <sys/stat.h>
 #include "devoptab_fs.h"
 
+static inline FSMode
+__wut_fs_convert_mode(mode_t mode)
+{
+   // Convert normal Unix octal permission bits into CafeOS hexadecimal permission bits
+   return (FSMode) (((mode & S_IRWXU) << 2) | ((mode & S_IRWXG) << 1) | (mode & S_IRWXO));
+}
+
 int
 __wut_fs_chmod(struct _reent *r,
                const char *path,
@@ -18,9 +26,11 @@ __wut_fs_chmod(struct _reent *r,
       return -1;
    }
 
+   FSMode translatedMode = __wut_fs_convert_mode(mode);
+
    FSInitCmdBlock(&cmd);
    status = FSChangeMode(__wut_devoptab_fs_client, &cmd, fixedPath,
-                         (FSMode)mode, FS_ERROR_FLAG_ALL);
+                         translatedMode, 0x777, FS_ERROR_FLAG_ALL);
    free(fixedPath);
    if (status < 0) {
       r->_errno = __wut_fs_translate_error(status);