diff --git a/rust/src/zstd_cli.rs b/rust/src/zstd_cli.rs
index 291a046ec..db33cb801 100644
--- a/rust/src/zstd_cli.rs
+++ b/rust/src/zstd_cli.rs
@@ -157,6 +157,7 @@ unsafe extern "C" {
     fn FIO_setContentSize(prefs: *mut FIO_prefs_t, value: c_int);
     fn FIO_setAsyncIOFlag(prefs: *mut FIO_prefs_t, value: c_int);
     fn FIO_setPassThroughFlag(prefs: *mut FIO_prefs_t, value: c_int);
+    fn FIO_setPatchFromMode(prefs: *mut FIO_prefs_t, value: c_int);
     fn FIO_setMMapDict(prefs: *mut FIO_prefs_t, value: c_int);
     fn FIO_setNbFilesTotal(ctx: *mut FIO_ctx_t, value: c_int);
     fn FIO_setHasStdinInput(ctx: *mut FIO_ctx_t, value: c_int);
@@ -1240,6 +1241,10 @@ unsafe fn apply_preferences(cli: &Cli, prefs: *mut FIO_prefs_t, ctx: *mut FIO_ct
         if let Some(value) = cli.pass_through {
             FIO_setPassThroughFlag(prefs, value);
         }
+        /* `FIO_createPreferences()` leaves this field unspecified. The Rust
+         * frontend does not yet parse --patch-from, so explicitly keep the
+         * C file-I/O backend in ordinary dictionary mode. */
+        FIO_setPatchFromMode(prefs, 0);
         FIO_setContentSize(prefs, cli.content_size);
         if let Some(value) = cli.dict_id {
             FIO_setDictIDFlag(prefs, value);