diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 9ec65ab1b..1f6d29260 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -62,8 +62,9 @@ jobs:
 
       - name: Prepare for publish
         run: |
+          sh install-offline.sh
           mkdir rust-bindings/cpp
-          cp -r src lib tests uint128_t python-bindings c-bindings CMakeLists.txt rust-bindings/cpp
+          cp -r src lib tests uint128_t python-bindings c-bindings CMakeLists.txt thirdparty rust-bindings/cpp
 
       - name: Publish to crates.io (dry run)
         # We use `--allow-dirty` because the `cpp` folder is copied into the working directory.
diff --git a/rust-bindings/build.rs b/rust-bindings/build.rs
index 2b7b11cd2..1a355968c 100644
--- a/rust-bindings/build.rs
+++ b/rust-bindings/build.rs
@@ -18,12 +18,18 @@ fn main() {
             .to_path_buf();
     }
 
+    let build_offline = cpp_dir.join("thirdparty").try_exists().unwrap();
+
     let dst = Config::new(cpp_dir.as_path())
         .build_target("chiapos_static")
         .define("BUILD_STATIC_CHIAPOS_LIBRARY", "ON")
         .define(
             "BUILD_OFFLINE",
-            env::var("BUILD_OFFLINE").unwrap_or_else(|_| "OFF".to_string()),
+            if build_offline {
+                "ON".to_string()
+            } else {
+                "OFF".to_string()
+            },
         )
         .build();