diff --git a/trezorlib/client.py b/trezorlib/client.py
index d17be03..552d73e 100644
--- a/trezorlib/client.py
+++ b/trezorlib/client.py
@@ -1,4 +1,5 @@
 import os
+import time
 import binascii
 import hashlib
 import unicodedata
@@ -433,15 +434,106 @@ class ProtocolMixin(object):
         return msg
 
     @field('serialized_tx')
-    @expect(proto.TxRequest)
+    @expect(types.TxRequestSerializedType)
     def simple_sign_tx(self, coin_name, inputs, outputs):
         # TODO Deserialize tx and check if inputs/outputs fits
         msg = self._prepare_simple_sign_tx(coin_name, inputs, outputs)
-        return self.call(msg)
+        return self.call(msg).serialized
+
+    def _prepare_sign_tx(self, coin_name, inputs, outputs):
+        tx = types.TransactionType()
+        tx.inputs.extend(inputs)
+        tx.outputs.extend (outputs)
+
+        txes = {}
+        txes[''] = tx
+
+        known_hashes = []
+        for inp in inputs:
+            if inp.prev_hash in known_hashes:
+                continue
+
+            txes[inp.prev_hash] = self.tx_api.get_tx(binascii.hexlify(inp.prev_hash))
+            known_hashes.append(inp.prev_hash)
+
+        return txes
 
     def sign_tx(self, coin_name, inputs, outputs):
         # Temporary solution, until streaming is implemented in the firmware
-        return self.simple_sign_tx(coin_name, inputs, outputs)
+        # return self.simple_sign_tx(coin_name, inputs, outputs)
+
+        start = time.time()
+        txes = self._prepare_sign_tx(coin_name, inputs, outputs)
+
+        try:
+            self.transport.session_begin()
+
+            # Prepare and send initial message
+            tx = proto.SignTx()
+            tx.inputs_count = len(inputs)
+            tx.outputs_count = len(outputs)
+            tx.coin_name = coin_name
+            res = self.call(tx)
+
+            # Prepare structure for signatures
+            signatures = [None] * len(inputs)
+            serialized_tx = ''
+
+            counter = 0
+            while True:
+                counter += 1
+
+                if isinstance(res, proto.Failure):
+                    raise CallException("Signing failed")
+
+                if not isinstance(res, proto.TxRequest):
+                    raise CallException("Unexpected message")
+
+                # If there's some part of signed transaction, let's add it
+                if res.HasField('serialized_tx'):
+                    print "!!! RECEIVED PART OF SERIALIED TX (%d BYTES)" % len(res.serialized_tx)
+                    serialized_tx += res.serialized_tx
+
+                if res.HasField('signature_index') and res.HasField('signature'):
+                    print "!!! SIGNED INPUT", res.signature_index
+                    signatures[res.signature_index] = res.signature
+
+                if res.request_type == types.TXFINISHED:
+                    # Device didn't ask for more information, finish workflow
+                    break
+
+                # Device asked for one more information, let's process it.
+                current_tx = txes[res.tx_hash]
+
+                if res.request_type == types.TXMETA:
+                    print "REQUESTING META OF", binascii.hexlify(res.tx_hash)
+                    msg = types.TransactionType()
+                    msg.version = current_tx.version
+                    msg.lock_time = current_tx.lock_time
+                    res = self.call(proto.TxAck(tx=msg))
+                    continue
+
+                elif res.request_type == types.TXINPUT:
+                    print "REQUESTING INPUT", res.request_index, "OF", binascii.hexlify(res.tx_hash)
+                    msg = types.TransactionType()
+                    msg.inputs.extend([current_tx.inputs[res.request_index], ])
+                    res = self.call(proto.TxAck(tx=msg))
+                    continue
+
+                elif res.request_type == types.TXOUTPUT:
+                    print "REQUESTING OUTOUT", res.request_index, "OF", binascii.hexlify(res.tx_hash)
+                    msg = types.TransactionType()
+                    msg.outputs.extend([current_tx.outputs[res.request_index], ])
+                    res = self.call(proto.TxAck(tx=msg))
+                    continue
+
+        finally:
+            self.transport.session_end()
+
+        print "SIGNED IN %.03f SECONDS, CALLED %d MESSAGES, %d BYTES" % \
+                (time.time() - start, counter, len(serialized_tx))
+
+        return (signatures, serialized_tx)
 
     @field('message')
     @expect(proto.Success)