diff --git a/pySim/commands.py b/pySim/commands.py
index d123e67d..ba37876b 100644
--- a/pySim/commands.py
+++ b/pySim/commands.py
@@ -407,7 +407,7 @@ class SimCardCommands:
         if len(rand) != 32:
             raise ValueError('Invalid rand')
         self.select_path(['3f00', '7f20'])
-        return self._tp.send_apdu(self.cla_byte + '88000010' + rand)
+        return self._tp.send_apdu('a0' + '88000010' + rand)
 
     def authenticate(self, rand: str, autn: str, context='3g'):
         """Execute AUTHENTICATE (USIM/ISIM).