diff --git a/.travis.yml b/.travis.yml
index 99ba39c1b..926cea97e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -21,7 +21,7 @@ install:
   - pip install coveralls
   - yes | pip uninstall neo-boa neocore
   - pip install -e git+https://github.com/CityOfZion/neo-boa@development#egg=neo-boa
-  - pip install -e git+https://github.com/CityOfZion/neo-python-core@master#egg=neocore
+  - pip install -e git+https://github.com/CityOfZion/neo-python-core@development#egg=neocore
 
 env:
   - NEOPYTHON_UNITTEST=1
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index dcaac22ea..f9151a787 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -11,6 +11,7 @@ All notable changes to this project are documented in this file.
 - Support cancelling actions with ``KeyboardInterrupt``
 - Enhance output of `wallet` cli command
 - Fixed size calculation for `RegisterTransaction`
+- Support updating np-core to throw exceptions instead of logging errors `#888 <https://github.com/CityOfZion/neo-python/issues/888>`_
 
 
 [0.8.4] 2019-02-14
diff --git a/neo/Core/BlockBase.py b/neo/Core/BlockBase.py
index cfb5921bb..75c26a1b9 100644
--- a/neo/Core/BlockBase.py
+++ b/neo/Core/BlockBase.py
@@ -119,7 +119,7 @@ def Deserialize(self, reader):
         """
         self.__hash = None
         self.DeserializeUnsigned(reader)
-        byt = reader.ReadByte()
+        byt = ord(reader.ReadByte())
         if int(byt) != 1:
             raise Exception('Incorrect format')
 
diff --git a/neo/Core/FunctionCode.py b/neo/Core/FunctionCode.py
index f54b3c13f..7e8038349 100644
--- a/neo/Core/FunctionCode.py
+++ b/neo/Core/FunctionCode.py
@@ -84,7 +84,7 @@ def Deserialize(self, reader):
         """
         self.Script = reader.ReadVarBytes()
         self.ParameterList = reader.ReadVarBytes()
-        self.ReturnType = reader.ReadByte()
+        self.ReturnType = ord(reader.ReadByte())
 
     def Serialize(self, writer):
         """
diff --git a/neo/Core/Header.py b/neo/Core/Header.py
index 551263702..f1c1e9dc4 100644
--- a/neo/Core/Header.py
+++ b/neo/Core/Header.py
@@ -36,7 +36,7 @@ def Deserialize(self, reader):
             reader (neo.IO.BinaryReader):
         """
         super(Header, self).Deserialize(reader)
-        if reader.ReadByte() != 0:
+        if ord(reader.ReadByte()) != 0:
             raise Exception('Incorrect Header Format')
 
     def Equals(self, other):
diff --git a/neo/Core/State/AssetState.py b/neo/Core/State/AssetState.py
index 948feaa8a..96d887bae 100644
--- a/neo/Core/State/AssetState.py
+++ b/neo/Core/State/AssetState.py
@@ -103,19 +103,19 @@ def Deserialize(self, reader):
         """
         super(AssetState, self).Deserialize(reader)
         self.AssetId = reader.ReadUInt256()
-        self.AssetType = reader.ReadByte()
+        self.AssetType = ord(reader.ReadByte())
         self.Name = reader.ReadVarString()
 
         position = reader.stream.tell()
 
         try:
             self.Amount = reader.ReadFixed8()
-        except Exception as e:
+        except Exception:
             reader.stream.seek(position)
             self.Amount = reader.ReadFixed8()
 
         self.Available = reader.ReadFixed8()
-        self.Precision = reader.ReadByte()
+        self.Precision = ord(reader.ReadByte())
 
         # fee mode
         reader.ReadByte()
diff --git a/neo/Core/State/StateBase.py b/neo/Core/State/StateBase.py
index 89d40b2fd..c94423456 100644
--- a/neo/Core/State/StateBase.py
+++ b/neo/Core/State/StateBase.py
@@ -36,7 +36,7 @@ def Deserialize(self, reader):
         Raises:
             Exception: if the state version is incorrect.
         """
-        sv = reader.ReadByte()
+        sv = ord(reader.ReadByte())
         if sv != self.StateVersion:
             raise Exception("Incorrect State format")
 
diff --git a/neo/Core/State/StateDescriptor.py b/neo/Core/State/StateDescriptor.py
index 704026eb5..33ddcd5e9 100644
--- a/neo/Core/State/StateDescriptor.py
+++ b/neo/Core/State/StateDescriptor.py
@@ -45,7 +45,7 @@ def Deserialize(self, reader: BinaryReader):
             reader (neocore.IO.BinaryReader):
         """
 
-        self.Type = StateType(reader.ReadByte())
+        self.Type = StateType(ord(reader.ReadByte()))
 
         self.Key = reader.ReadVarBytes(max=100)
         self.Field = reader.ReadVarString(max=32).decode('utf-8')
diff --git a/neo/Core/State/UnspentCoinState.py b/neo/Core/State/UnspentCoinState.py
index 386e61138..fedb6b218 100644
--- a/neo/Core/State/UnspentCoinState.py
+++ b/neo/Core/State/UnspentCoinState.py
@@ -84,7 +84,7 @@ def Deserialize(self, reader):
         blen = reader.ReadVarInt()
         self.Items = [0] * blen
         for i in range(0, blen):
-            self.Items[i] = int.from_bytes(reader.ReadByte(do_ord=False), 'little')
+            self.Items[i] = int.from_bytes(reader.ReadByte(), 'little')
 
     @staticmethod
     def DeserializeFromDB(buffer):
diff --git a/neo/Core/TX/RegisterTransaction.py b/neo/Core/TX/RegisterTransaction.py
index d4b08917f..dabe85f03 100644
--- a/neo/Core/TX/RegisterTransaction.py
+++ b/neo/Core/TX/RegisterTransaction.py
@@ -103,10 +103,10 @@ def DeserializeExclusiveData(self, reader):
             reader (neo.IO.BinaryReader):
         """
         self.Type = TransactionType.RegisterTransaction
-        self.AssetType = reader.ReadByte()
+        self.AssetType = ord(reader.ReadByte())
         self.Name = reader.ReadVarString()
         self.Amount = reader.ReadFixed8()
-        self.Precision = reader.ReadByte()
+        self.Precision = ord(reader.ReadByte())
         self.Owner = ECDSA.Deserialize_Secp256r1(reader)
         #        self.Owner = ecdsa.G
         self.Admin = reader.ReadUInt160()
diff --git a/neo/Core/TX/Transaction.py b/neo/Core/TX/Transaction.py
index 6a70b0ac5..a4eea2dc0 100644
--- a/neo/Core/TX/Transaction.py
+++ b/neo/Core/TX/Transaction.py
@@ -441,7 +441,7 @@ def DeserializeFrom(reader):
         Returns:
             Transaction:
         """
-        ttype = reader.ReadByte()
+        ttype = ord(reader.ReadByte())
         tx = None
 
         from neo.Core.TX.RegisterTransaction import RegisterTransaction
@@ -499,7 +499,7 @@ def DeserializeUnsigned(self, reader):
         Raises:
             Exception: if transaction type is incorrect.
         """
-        txtype = reader.ReadByte()
+        txtype = ord(reader.ReadByte())
         if txtype != int.from_bytes(self.Type, 'little'):
             raise Exception('incorrect type {}, wanted {}'.format(txtype, int.from_bytes(self.Type, 'little')))
         self.DeserializeUnsignedWithoutType(reader)
@@ -511,7 +511,7 @@ def DeserializeUnsignedWithoutType(self, reader):
         Args:
             reader (neo.IO.BinaryReader):
         """
-        self.Version = reader.ReadByte()
+        self.Version = ord(reader.ReadByte())
         self.DeserializeExclusiveData(reader)
         self.Attributes = reader.ReadSerializableArray('neo.Core.TX.TransactionAttribute.TransactionAttribute',
                                                        max=self.MAX_TX_ATTRIBUTES)
diff --git a/neo/Core/TX/TransactionAttribute.py b/neo/Core/TX/TransactionAttribute.py
index f536f0d6c..85a38df08 100644
--- a/neo/Core/TX/TransactionAttribute.py
+++ b/neo/Core/TX/TransactionAttribute.py
@@ -84,7 +84,7 @@ def Deserialize(self, reader):
         Args:
             reader (neo.IO.BinaryReader):
         """
-        usage = reader.ReadByte()
+        usage = ord(reader.ReadByte())
         self.Usage = usage
 
         if usage == TransactionAttributeUsage.ContractHash or usage == TransactionAttributeUsage.Vote or \
@@ -99,7 +99,7 @@ def Deserialize(self, reader):
 
         elif usage == TransactionAttributeUsage.DescriptionUrl:
 
-            self.Data = reader.ReadBytes(reader.ReadByte())
+            self.Data = reader.ReadBytes(ord(reader.ReadByte()))
 
         elif usage == TransactionAttributeUsage.Description or usage >= TransactionAttributeUsage.Remark:
             self.Data = reader.ReadVarBytes(max=self.MAX_ATTR_DATA_SIZE)
diff --git a/neo/Network/Payloads/InvPayload.py b/neo/Network/Payloads/InvPayload.py
index b82bccd48..aa29128ab 100644
--- a/neo/Network/Payloads/InvPayload.py
+++ b/neo/Network/Payloads/InvPayload.py
@@ -42,7 +42,7 @@ def Deserialize(self, reader):
         Args:
             reader (neo.IO.BinaryReader):
         """
-        self.Type = reader.ReadByte()
+        self.Type = ord(reader.ReadByte())
         self.Hashes = reader.ReadHashes()
 
     def Serialize(self, writer):
diff --git a/neo/Prompt/Commands/Invoke.py b/neo/Prompt/Commands/Invoke.py
index be73b4c2f..ff63117cb 100644
--- a/neo/Prompt/Commands/Invoke.py
+++ b/neo/Prompt/Commands/Invoke.py
@@ -660,6 +660,10 @@ def gather_signatures(context, itx, owners):
             else:
                 print("Public Key does not match address %s " % next_addr)
 
+        except ValueError:
+            # expected from ECDSA if public key is invalid
+            print(f"Invalid public key: {items[0]}")
+            do_exit = True
         except EOFError:
             # Control-D pressed: quit
             do_exit = True
diff --git a/neo/Prompt/Utils.py b/neo/Prompt/Utils.py
index e9698832a..7a2a98bfb 100644
--- a/neo/Prompt/Utils.py
+++ b/neo/Prompt/Utils.py
@@ -329,7 +329,10 @@ def gather_param(index, param_type, do_continue=True):
         elif ptype == ContractParameterType.Boolean:
             return bool(result), False
         elif ptype == ContractParameterType.PublicKey:
-            return ECDSA.decode_secp256r1(result).G, False
+            try:
+                return ECDSA.decode_secp256r1(result).G, False
+            except ValueError:
+                return None, True
         elif ptype == ContractParameterType.ByteArray:
             if isinstance(result, str) and len(result) == 34 and result[0] == 'A':
                 return Helper.AddrStrToScriptHash(result).Data, False
diff --git a/neo/Prompt/test_utils.py b/neo/Prompt/test_utils.py
index 476f8e00f..60f55ad80 100644
--- a/neo/Prompt/test_utils.py
+++ b/neo/Prompt/test_utils.py
@@ -270,6 +270,13 @@ def test_gather_param(self):
             wallet = None
             os.remove(WalletFixtureTestCase.wallet_1_dest())
 
+        # test ContractParameterType.PublicKey with bad public key
+        with mock.patch('neo.Prompt.Utils.get_input_prompt', return_value="blah") as fake_prompt:
+
+            result, abort = Utils.gather_param(0, ContractParameterType.PublicKey)
+            self.assertIsNone(result)
+            self.assertTrue(abort)
+
         # test unknown ContractParameterType
         with mock.patch('neo.Prompt.Utils.get_input_prompt', return_value="9698b1cac6ce9cbe8517e490778525b929e01903") as fake_prompt:
 
diff --git a/neo/SmartContract/ContractParameterContext.py b/neo/SmartContract/ContractParameterContext.py
index 039e491de..2abf4905c 100755
--- a/neo/SmartContract/ContractParameterContext.py
+++ b/neo/SmartContract/ContractParameterContext.py
@@ -165,10 +165,14 @@ def AddSignature(self, contract, pubkey, signature):
             ms = MemoryStream(binascii.unhexlify(contract.Script))
             reader = BinaryReader(ms)
             numr = reader.ReadUInt8()
-            while reader.ReadUInt8() == 33:
-                ecpoint = ecdsa.ec.decode_from_hex(binascii.hexlify(reader.ReadBytes(33)).decode())
-                points.append(ecpoint)
-            ms.close()
+            try:
+                while reader.ReadUInt8() == 33:
+                    ecpoint = ecdsa.ec.decode_from_hex(binascii.hexlify(reader.ReadBytes(33)).decode())
+                    points.append(ecpoint)
+            except ValueError:
+                return False
+            finally:
+                ms.close()
 
             if pubkey not in points:
                 return False
diff --git a/neo/SmartContract/StateMachine.py b/neo/SmartContract/StateMachine.py
index fb1f88207..571919eec 100644
--- a/neo/SmartContract/StateMachine.py
+++ b/neo/SmartContract/StateMachine.py
@@ -146,7 +146,10 @@ def Asset_Create(self, engine: ExecutionEngine):
 
         ownerData = engine.CurrentContext.EvaluationStack.Pop().GetByteArray()
 
-        owner = ECDSA.decode_secp256r1(ownerData, unhex=False).G
+        try:
+            owner = ECDSA.decode_secp256r1(ownerData, unhex=False).G
+        except ValueError:
+            return False
 
         if owner.IsInfinity:
             return False
diff --git a/neo/SmartContract/StateReader.py b/neo/SmartContract/StateReader.py
index be31368be..a5cdd0448 100644
--- a/neo/SmartContract/StateReader.py
+++ b/neo/SmartContract/StateReader.py
@@ -346,7 +346,10 @@ def Runtime_CheckWitness(self, engine: ExecutionEngine):
             result = self.CheckWitnessHash(engine, UInt160(data=hashOrPubkey))
 
         elif len(hashOrPubkey) == 33:
-            point = ECDSA.decode_secp256r1(hashOrPubkey, unhex=False).G
+            try:
+                point = ECDSA.decode_secp256r1(hashOrPubkey, unhex=False).G
+            except ValueError:
+                return False
             result = self.CheckWitnessPubkey(engine, point)
         else:
             return False
diff --git a/neo/VM/ExecutionEngine.py b/neo/VM/ExecutionEngine.py
index 110137144..318d315b7 100644
--- a/neo/VM/ExecutionEngine.py
+++ b/neo/VM/ExecutionEngine.py
@@ -160,7 +160,7 @@ def ExecuteOp(self, opcode, context: ExecutionContext):
                 estack.PushT(bytearray(0))
 
             elif opcode == PUSHDATA1:
-                lenngth = context.OpReader.ReadByte()
+                lenngth = ord(context.OpReader.ReadByte())
                 estack.PushT(bytearray(context.OpReader.SafeReadBytes(lenngth)))
             elif opcode == PUSHDATA2:
                 estack.PushT(context.OpReader.SafeReadBytes(context.OpReader.ReadUInt16()))
@@ -887,8 +887,8 @@ def ExecuteOp(self, opcode, context: ExecutionContext):
 
             # stack isolation
             elif opcode == CALL_I:
-                rvcount = context.OpReader.ReadByte()
-                pcount = context.OpReader.ReadByte()
+                rvcount = ord(context.OpReader.ReadByte())
+                pcount = ord(context.OpReader.ReadByte())
 
                 if estack.Count < pcount:
                     return self.VM_FAULT_and_report(VMFault.UNKNOWN_STACKISOLATION)
@@ -906,8 +906,8 @@ def ExecuteOp(self, opcode, context: ExecutionContext):
                 if self._Table is None:
                     return self.VM_FAULT_and_report(VMFault.UNKNOWN_STACKISOLATION2)
 
-                rvcount = context.OpReader.ReadByte()
-                pcount = context.OpReader.ReadByte()
+                rvcount = ord(context.OpReader.ReadByte())
+                pcount = ord(context.OpReader.ReadByte())
 
                 if estack.Count < pcount:
                     return self.VM_FAULT_and_report(VMFault.UNKNOWN_STACKISOLATION)
@@ -998,7 +998,7 @@ def StepInto(self):
         if self.CurrentContext.InstructionPointer >= len(self.CurrentContext.Script):
             op = RET
         else:
-            op = self.CurrentContext.OpReader.ReadByte(do_ord=False)
+            op = self.CurrentContext.OpReader.ReadByte()
 
         self.ops_processed += 1
 
diff --git a/neo/VM/InteropService.py b/neo/VM/InteropService.py
index 051012b31..8cdde5b0a 100644
--- a/neo/VM/InteropService.py
+++ b/neo/VM/InteropService.py
@@ -81,7 +81,7 @@ def DeserializeStackItem(reader):
         if stype == StackItemType.ByteArray:
             return ByteArray(reader.ReadVarBytes())
         elif stype == StackItemType.Boolean:
-            return Boolean(reader.ReadByte())
+            return Boolean(ord(reader.ReadByte()))
         elif stype == StackItemType.Integer:
             return Integer(BigInteger.FromBytes(reader.ReadVarBytes(), signed=True))
         elif stype == StackItemType.Array: