diff --git a/README.md b/README.md
index e93821a..98e4b28 100644
--- a/README.md
+++ b/README.md
@@ -7,6 +7,7 @@ libplum tries each protocol in order (PCP → NAT-PMP → UPnP-IGD) and falls ba
 ## Installation
 
 ```bash
+git submodule update --init
 nimble install
 ```