diff --git a/README.md b/README.md
index 4cf37642232..fe462597357 100644
--- a/README.md
+++ b/README.md
@@ -238,7 +238,7 @@ First a RSA key must be created with `openssl(1)` or `ssh-keygen(1)`:
 
 or
 
-	$ ssh-keygen -t rsa -b 4096 -f privkey.pem
+	$ ssh-keygen -t rsa -b 4096 -m PEM -f privkey.pem
 
 > Only RSA keys in PEM format are currently accepted by xbps.