diff --git a/README.md b/README.md
index 3e468e090..912c73a7d 100644
--- a/README.md
+++ b/README.md
@@ -127,6 +127,7 @@ Begin by cloning the repository and building the Docker container:
 ```sh
 git clone https://github.com/rustdesk/rustdesk
 cd rustdesk
+git submodule update --init --recursive
 docker build -t "rustdesk-builder" .
 ```