diff --git a/INSTALL.md b/INSTALL.md
index d63f58e..a211e99 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -102,7 +102,7 @@ Build. This will also automatically install the GHC Haskell compiler.
 
 Generate a new SSH key with a blank password:
 
-    $ ssh-keygen -t rsa -f config/ssh-host-key
+    $ ssh-keygen -t rsa -m PEM -f config/ssh-host-key
 
 Update the settings to specify correct database connection details and other
 settings.