diff --git a/etheno/etheno.py b/etheno/etheno.py
index 4667a61..041d8f4 100644
--- a/etheno/etheno.py
+++ b/etheno/etheno.py
@@ -303,7 +303,6 @@ def post(self, data):
             plugin.before_post(data)
 
         method = data['method']
-        
         args = ()
         kwargs = {}
         if 'params' in data:
@@ -316,12 +315,15 @@ def post(self, data):
                     del kwargs['from']
             else:
                 args = data['params']
+
         if self.master_client is None:
             ret = None
         else:
             if method == 'eth_getTransactionReceipt':
                 # for eth_getTransactionReceipt, make sure we block until all clients have mined the transaction
                 ret = self.master_client.wait_for_transaction(data['params'][0])
+                if 'id' in data and 'id' in ret:
+                    ret['id'] = data['id']
             else:
                 try:
                     ret = self.master_client.post(data)
@@ -342,6 +344,7 @@ def post(self, data):
                         kwargs['rpc_client_result'] = ret
                         results.append(function(*args, **kwargs))
                     else:
+                        self.logger.warn(f"Function {method} of {client} is None!")
                         results.append(None)
                 elif isinstance(client, SelfPostingClient):
                     if method == 'eth_getTransactionReceipt':
diff --git a/etheno/logger.py b/etheno/logger.py
index 66ca848..6d842cd 100644
--- a/etheno/logger.py
+++ b/etheno/logger.py
@@ -140,7 +140,7 @@ def _add_child(self, child):
             raise ValueError("Cannot double-add child logger %s to logger %s" % (child.name, self.name))
         self.children.append(child)
         if self.directory is not None:
-            child.save_to_directory(os.path.join(self.directory, child.name))
+            child.save_to_directory(os.path.join(self.directory, child.name.replace(os.sep, '-')))
         else:
             child._tmpdir = tempfile.TemporaryDirectory()
             child.save_to_directory(child._tmpdir.name)
@@ -219,7 +219,7 @@ def save_to_directory(self, path):
             raise ValueError("Logger %s's save directory is already set to %s" % (self.name, path))
         self._directory = os.path.realpath(path)
         os.makedirs(path, exist_ok=True)
-        self.save_to_file(os.path.join(path, "%s.log" % self.name), include_descendants=False, log_level=DEBUG)
+        self.save_to_file(os.path.join(path, "%s.log" % self.name.replace(os.sep, '-')), include_descendants=False, log_level=DEBUG)
         for child in self.children:
             child.save_to_directory(os.path.join(path, child.name))
 
diff --git a/etheno/truffle.py b/etheno/truffle.py
index 7d76e77..298b999 100644
--- a/etheno/truffle.py
+++ b/etheno/truffle.py
@@ -19,7 +19,7 @@ def run_migrate(self):
 
     def run(self, args):
         self._running = True
-        if isinstance(args, Sequence):
+        if isinstance(args, Sequence) and not isinstance(args, str) and not isinstance(args, bytes):
             if not isinstance(args, list):
                 args = list(args)
         else:
diff --git a/examples/BrokenMetaCoin/contracts/ConvertLib.sol b/examples/BrokenMetaCoin/contracts/ConvertLib.sol
index 9bbed83..5d83fa9 100644
--- a/examples/BrokenMetaCoin/contracts/ConvertLib.sol
+++ b/examples/BrokenMetaCoin/contracts/ConvertLib.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.4;
+pragma solidity ^0.5.0;
 
 library ConvertLib{
 	function convert(uint amount,uint conversionRate) public pure returns (uint convertedAmount)
diff --git a/examples/BrokenMetaCoin/contracts/MetaCoin.sol b/examples/BrokenMetaCoin/contracts/MetaCoin.sol
index a8a7816..25494f2 100644
--- a/examples/BrokenMetaCoin/contracts/MetaCoin.sol
+++ b/examples/BrokenMetaCoin/contracts/MetaCoin.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.18;
+pragma solidity ^0.5.0;
 
 import "./ConvertLib.sol";
 
@@ -26,7 +26,7 @@ contract MetaCoin {
                  return metadata[key];
         }
 
-        function backdoor() {
+        function backdoor() public {
                  selfdestruct(msg.sender);
         }
 
diff --git a/examples/BrokenMetaCoin/contracts/Migrations.sol b/examples/BrokenMetaCoin/contracts/Migrations.sol
index b83fdd0..89b4d5c 100644
--- a/examples/BrokenMetaCoin/contracts/Migrations.sol
+++ b/examples/BrokenMetaCoin/contracts/Migrations.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.2;
+pragma solidity ^0.5.0;
 
 contract Migrations {
   address public owner;
diff --git a/examples/BrokenMetaCoin/run_etheno.sh b/examples/BrokenMetaCoin/run_etheno.sh
index 7504ada..b77bcb4 100755
--- a/examples/BrokenMetaCoin/run_etheno.sh
+++ b/examples/BrokenMetaCoin/run_etheno.sh
@@ -1,3 +1,10 @@
+# First, remove the Truffle build directory.
+# This shouldn't be necessary, but Truffle will often fail with
+# confusing error messages if it is upgraded between builds.
+# So, we just rebuild everything from scratch each time to ensure
+# that it always works.
+rm -rf build
+
 echo "Running the custom Manticore script ExploitMetaCoinManticoreScript.py"
 # Set the max depth for Manticore to 2 because this script only needs to
 # find a sequence of two transactions to exploit the bug