diff --git a/algorand/wormhole_core.py b/algorand/wormhole_core.py
index 83e519f64..9daec1443 100644
--- a/algorand/wormhole_core.py
+++ b/algorand/wormhole_core.py
@@ -259,13 +259,9 @@ def getCoreContracts(   genTeal, approve_name, clear_name,
                         MagicAssert(len.load() > Int(0)),  
 
                         Pop(blob.write(Int(3), Int(0), Extract(Txn.application_args[1], off.load(), Int(1) + (Int(20) * len.load())))),
-                        # Make this block expire.. as long as it is
-                        # not being used to sign itself.  We stick the
-                        # expiration 1000 bytes into the account...
-                        #
-                        # 19200 is approx 24 hours assuming a 4.5 seconds per block   (24 * 3600 / 4.5) = 19200
+
                         If(Txn.accounts[3] != Txn.accounts[2],
-                           Pop(blob.write(Int(2), Int(1000), Itob(Txn.first_valid() + Int(19200))))),
+                           Pop(blob.write(Int(2), Int(1000), Itob(Global.latest_timestamp() + Int(86400))))),
                         blob.meta(Int(3), Bytes("guardian"))
                     ])],
                     [a.load() == Int(3), Seq([
@@ -379,12 +375,14 @@ def getCoreContracts(   genTeal, approve_name, clear_name,
                 blob.checkMeta(Int(2), Bytes("guardian")),
                 # Lets grab the total keyset
                 total_guardians.store(blob.get_byte(Int(2), Int(0))),
+                MagicAssert(total_guardians.load() > Int(0)),
+
                 guardian_keys.store(blob.read(Int(2), Int(1), Int(1) + Int(20) * total_guardians.load())),
 
                 # I wonder if this is an expired guardian set
                 s.store(Btoi(blob.read(Int(2), Int(1000), Int(1008)))),
                 If(s.load() != Int(0),
-                   MagicAssert(Txn.first_valid() < s.load())),
+                   MagicAssert(Global.latest_timestamp() < s.load())),
 
                 hits.store(Bytes("base16", "0x00000000")),