diff --git a/sysmo_isim_sja2.py b/sysmo_isim_sja2.py
index a83c750..e2a9f01 100644
--- a/sysmo_isim_sja2.py
+++ b/sysmo_isim_sja2.py
@@ -314,18 +314,18 @@ class SYSMO_ISIMSJA2_FILE_EF_USIM_SQN:
 	# Flag1:
 	ind_size_bits = 5 # speficy file length by 2^ind_len
 	sqn_check_enabled = True # perform SQN checks below
-	sqn_age_limit_enabled = False # perform age limit check: (SQNms-SQN) <= AGE_LIMIT)
+	sqn_age_limit_enabled = True # perform age limit check: (SQNms-SQN) <= AGE_LIMIT)
 	sqn_max_delta_enabled = True # perform delta max check: (SWN-SQNms) <= DELTA MAX)
 	sqn_check_skip_first = True # accept any SQN on the first authentication
 
 	# Flag2:
 	conceal_autn = True # Conceal the value of AUTN
 	conceal_auts = True # Conceal the value of AUTS
-	no_amf_clear = False # Do not clear AMF when computing MAC-S
+	no_amf_clear = True # Do not clear AMF when computing MAC-S
 
 	# Data:
-	max_delta = 2**28 << ind_size_bits
-	age_limit = 2**28 << ind_size_bits
+	max_delta = 281474976710655
+	age_limit = 281474976710655
 	freshness_data = [0x00] * (6*2**ind_size_bits) # initalize to zero
 
 	def __init__(self, content = None):
@@ -848,17 +848,13 @@ class Sysmo_isim_sja2(Sysmo_usim):
 
 		self.sim.card.SELECT_ADF_USIM()
 		self.sim.select(SYSMO_ISIMSJA2_EF_USIM_SQN)
-		res = self._read_binary(self.sim.filelen)
-		ef = SYSMO_ISIMSJA2_FILE_EF_USIM_SQN(res.apdu)
-		ef.reset()
+		ef = SYSMO_ISIMSJA2_FILE_EF_USIM_SQN()
 		self.sim.update_binary(ef.encode())
 
 		if self.has_isim:
 		    self.sim.card.SELECT_ADF_ISIM()
 		    self.sim.select(SYSMO_ISIMSJA2_EF_USIM_SQN)
-		    res = self._read_binary(self.sim.filelen)
-		    ef = SYSMO_ISIMSJA2_FILE_EF_USIM_SQN(res.apdu)
-		    ef.reset()
+		    ef = SYSMO_ISIMSJA2_FILE_EF_USIM_SQN()
 		    self.sim.update_binary(ef.encode())
 
 		print("")