diff --git a/trezorctl b/trezorctl
index 3045942b6..132e47ce7 100755
--- a/trezorctl
+++ b/trezorctl
@@ -6,9 +6,12 @@ import argparse
 import json
 import base64
 import tempfile
+from trezorlib import types_pb2 as types
 from io import BytesIO
 
-from trezorlib.client import TrezorClient, TrezorClientDebug
+import sys
+
+from trezorlib.client import TrezorClient, TrezorClientDebug, CallException
 
 ether_units = {
     "wei":          1,
@@ -70,7 +73,7 @@ def get_transport(transport_string, path, **kwargs):
             if path == '' or path in d:
                 return HidTransport(d, **kwargs)
 
-        raise Exception("Device not found")
+        raise CallException(types.Failure_Other, "Device not found")
 
     if transport_string == 'udp':
         from trezorlib.transport_udp import UdpTransport
@@ -90,7 +93,7 @@ def get_transport(transport_string, path, **kwargs):
             if path == '' or d['path'] == binascii.hexlify(path):
                 return BridgeTransport(d, **kwargs)
 
-        raise Exception("Device not found")
+        raise CallException(types.Failure_Other, "Device not found")
 
     raise NotImplementedError("Unknown transport")
 
@@ -124,7 +127,7 @@ class Commands(object):
         if ' ' in value:
             value, unit = value.split(' ', 1)
             if unit.lower() not in ether_units:
-                raise Exception("Unrecognized ether unit %r", unit)
+                raise CallException(types.Failure_Other, "Unrecognized ether unit %r" % unit)
             value = int(value) * ether_units[unit.lower()]
         else:
             value = int(value)
@@ -196,7 +199,7 @@ class Commands(object):
             from PIL import Image
             im = Image.open(args.filename)
             if im.size != (128, 64):
-                raise Exception('Wrong size of the image')
+                raise CallException(types.Failure_Other, 'Wrong size of the image')
             im = im.convert('1')
             pix = im.load()
             img = ''
@@ -223,7 +226,7 @@ class Commands(object):
 
     def load_device(self, args):
         if not args.mnemonic and not args.xprv:
-            raise Exception("Please provide mnemonic or xprv")
+            raise CallException(types.Failure_Other, "Please provide mnemonic or xprv")
 
         if args.mnemonic:
             mnemonic = ' '.join(args.mnemonic)
@@ -313,7 +316,7 @@ class Commands(object):
             if fp[:8] == b'54525a52':
                 fp = binascii.unhexlify(fp)
             if fp[:4] != b'TRZR':
-                raise Exception("TREZOR firmware header expected")
+                raise CallException(types.Failure_FirmwareError, "TREZOR firmware header expected")
 
         print("Please confirm action on device...")
 
@@ -534,32 +537,39 @@ def qt_pin_func(input_text, message=None):
 def main():
     args = parse_args(Commands)
 
-    if args.cmd == 'list':
-        devices = list_usb()
-        if args.json:
-            print(json.dumps(devices))
+    try:
+
+        if args.cmd == 'list':
+            devices = list_usb()
+            if args.json:
+                print(json.dumps(devices))
+            else:
+                for dev in devices:
+                    if dev[1] != None:
+                        print("%s - debuglink enabled" % dev[0])
+                    else:
+                        print(dev[0])
+            return
+
+        transport = get_transport(args.transport, args.path)
+        if args.verbose:
+            client = TrezorClientDebug(transport)
         else:
-            for dev in devices:
-                if dev[1] != None:
-                    print("%s - debuglink enabled" % dev[0])
-                else:
-                    print(dev[0])
-        return
+            client = TrezorClient(transport)
 
-    transport = get_transport(args.transport, args.path)
-    if args.verbose:
-        client = TrezorClientDebug(transport)
-    else:
-        client = TrezorClient(transport)
+        cmds = Commands(client)
 
-    cmds = Commands(client)
+        res = args.func(cmds, args)
 
-    res = args.func(cmds, args)
+        if args.json:
+            print(json.dumps(res, sort_keys=True, indent=4))
+        else:
+            print(res)
+    except CallException as e:
+        status, message = e.args
+        sys.stderr.write('failure: {message}\n'.format(message=message))
+        exit(status)
 
-    if args.json:
-        print(json.dumps(res, sort_keys=True, indent=4))
-    else:
-        print(res)
 
 if __name__ == '__main__':
     main()