diff --git a/trezorlib/ckd_public.py b/trezorlib/ckd_public.py
index 1aee54e4f3..9b187880c3 100644
--- a/trezorlib/ckd_public.py
+++ b/trezorlib/ckd_public.py
@@ -32,20 +32,13 @@ from . import messages as proto
 
 PRIME_DERIVATION_FLAG = 0x80000000
 
-if sys.version_info < (3,):
-    def byteindex(data, index):
-        return ord(data[index])
-else:
-    def byteindex(data, index):
-        return data[index]
-
 
 def point_to_pubkey(point):
     order = SECP256k1.order
     x_str = number_to_string(point.x(), order)
     y_str = number_to_string(point.y(), order)
     vk = x_str + y_str
-    return struct.pack('B', (byteindex(vk, 63) & 1) + 2) + vk[0:32]  # To compressed key
+    return struct.pack('B', (vk[63] & 1) + 2) + vk[0:32]  # To compressed key
 
 
 def sec_to_public_pair(pubkey):
@@ -152,7 +145,7 @@ def deserialize(xpub):
     node.chain_code = data[13:45]
 
     key = data[45:-4]
-    if byteindex(key, 0) == 0:
+    if key[0] == 0:
         node.private_key = key[1:]
     else:
         node.public_key = key
diff --git a/trezorlib/client.py b/trezorlib/client.py
index 6f3e6a6732..ec77ceaa72 100644
--- a/trezorlib/client.py
+++ b/trezorlib/client.py
@@ -38,15 +38,9 @@ from .coins import coins_slip44
 from .debuglink import DebugLink
 from .protobuf import MessageType
 
-# Python2 vs Python3
-try:
-    input = raw_input
-except NameError:
-    pass
-
 
 if sys.version_info.major < 3:
-    warnings.warn("Trezorlib will stop supporting Python2 in next versions.", DeprecationWarning)
+    raise Exception("Trezorlib does not support Python 2 anymore.")
 
 # try:
 #     from PIL import Image
@@ -194,17 +188,11 @@ def session(f):
 
 
 def normalize_nfc(txt):
-    if sys.version_info[0] < 3:
-        if isinstance(txt, unicode):
-            return unicodedata.normalize('NFC', txt)
-        if isinstance(txt, str):
-            return unicodedata.normalize('NFC', txt.decode('utf-8'))
-    else:
-        if isinstance(txt, bytes):
-            return unicodedata.normalize('NFC', txt.decode('utf-8'))
-        if isinstance(txt, str):
-            return unicodedata.normalize('NFC', txt)
-    raise ValueError('unicode/str or bytes/str expected')
+    if isinstance(txt, bytes):
+        return unicodedata.normalize('NFC', txt.decode('utf-8'))
+    if isinstance(txt, str):
+        return unicodedata.normalize('NFC', txt)
+    raise ValueError('expected str or bytes argument')
 
 
 class BaseClient(object):
diff --git a/trezorlib/tools.py b/trezorlib/tools.py
index 4ff3b50e86..5ea9beeba1 100644
--- a/trezorlib/tools.py
+++ b/trezorlib/tools.py
@@ -22,17 +22,6 @@ import binascii
 import struct
 import sys
 
-if sys.version_info < (3,):
-    def byteindex(data, index):
-        return ord(data[index])
-
-    def iterbytes(data):
-        return (ord(char) for char in data)
-else:
-    def byteindex(data, index):
-        return data[index]
-    iterbytes = iter
-
 
 def Hash(data):
     return hashlib.sha256(hashlib.sha256(data).digest()).digest()
@@ -52,8 +41,8 @@ def hash_160_to_bc_address(h160, address_type):
 
 
 def compress_pubkey(public_key):
-    if byteindex(public_key, 0) == 4:
-        return bytes((byteindex(public_key, 64) & 1) + 2) + public_key[1:33]
+    if public_key[0] == 4:
+        return bytes((public_key[64] & 1) + 2) + public_key[1:33]
     raise ValueError("Pubkey is already compressed")