diff --git a/doc/doxygen/src/using-rust.md b/doc/doxygen/src/using-rust.md
index 7d38b61080..00559f44d2 100644
--- a/doc/doxygen/src/using-rust.md
+++ b/doc/doxygen/src/using-rust.md
@@ -125,7 +125,7 @@ $ rustup component add --toolchain nightly-2019-12-05 rustfmt rustc-dev
 $ cargo +nightly-2019-12-05 install c2rust
 $ git clone https://github.com/chrysn-pull-requests/c2rust -b for-riot
 $ cd c2rust
-$ cargo +nightly-2019-12-05 install --path c2rust
+$ cargo +nightly-2019-12-05 install --locked --path c2rust
 ```
 
 [cargo]: https://doc.rust-lang.org/cargo/