diff --git a/scapy/contrib/ikev2.py b/scapy/contrib/ikev2.py
index 3bf12e65bff..b1ffd8cdc17 100644
--- a/scapy/contrib/ikev2.py
+++ b/scapy/contrib/ikev2.py
@@ -568,7 +568,7 @@ class IKEv2_Payload(_IKEv2_Packet):
     name = "IKEv2 Payload"
     fields_desc = [
         ByteEnumField("next_payload", None, IKEv2PayloadTypes),
-        FlagsField("flags", 0, 8, ["critical"]),
+        FlagsField("flags", 0, 8, {0x80: "critical"}),
         ShortField("length", None),
         XStrLenField("load", "", length_from=lambda pkt: pkt.length - 4),
     ]
diff --git a/test/contrib/ikev2.uts b/test/contrib/ikev2.uts
index db503867fc1..9d51493daa1 100644
--- a/test/contrib/ikev2.uts
+++ b/test/contrib/ikev2.uts
@@ -28,8 +28,8 @@ a[IKEv2_Transform].show()
 
 = Build Ikev2 SA request packet
 
-a = IKEv2(init_SPI="MySPI",exch_type=34)/IKEv2_SA(prop=IKEv2_Proposal())
-assert raw(a) == b'MySPI\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00! "\x00\x00\x00\x00\x00\x00\x00\x00(\x00\x00\x00\x0c\x00\x00\x00\x08\x01\x01\x00\x00'
+a = IKEv2(init_SPI="MySPI",exch_type=34)/IKEv2_SA(flags="critical", prop=IKEv2_Proposal())
+assert raw(a) == b'MySPI\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00! "\x00\x00\x00\x00\x00\x00\x00\x00(\x00\x80\x00\x0c\x00\x00\x00\x08\x01\x01\x00\x00'
 
 = Build advanced IKEv2