diff --git a/doc/OS-X-Codesigning.txt b/doc/OS-X-Codesigning.txt
index b07dd66..049703b 100644
--- a/doc/OS-X-Codesigning.txt
+++ b/doc/OS-X-Codesigning.txt
@@ -42,10 +42,12 @@ Steps
 
    $ yubico-piv-tool -a import-certificate -s 9a -K DER -i mac_app.cer
    $ yubico-piv-tool -a import-certificate -s 9c -K DER -i mac_installer.cer
++
+NOTE: -K DER is available from version 0.1.3, with earlier convert to PEM and import.
 
 8. Set a new chuid in the applet to make sure nothing is cached for the key:
 
-   yubico-piv-tool -a set-chuid
+   $ yubico-piv-tool -a set-chuid
 
 9. Re-plug the Neo and make sure the certificates show up under the keychain
 "PIV_II" in Keychain Access.