1 files changed, 4 insertions, 0 deletions

diff --git a/README.md b/README.md
index ee94cc9..ce35bd6 100644
--- a/README.md
+++ b/README.md
@@ -16,6 +16,10 @@ To sign using a PIV-II smartcard such as the Yubikey, install `pkcs11-tool` from
 
     marginaltool -e pkcs11 -i <KEY ID> bc-digsign://sign?…
 
+If you need too specify a different PKCS#11 module, like `/usr/local/lib/libykcs11.so` for the Yubikey, set the module argument by running
+
+    marginaltool -e pkcs11 -m <MODULE PATH> -i <KEY ID> bc-digsign://sign?…
+
 The script will prompt for the PIN to unlock the smartcard. To find the key ID, run
 
     pkcs11-tool -O