diff --git a/aheui/aheui.py b/aheui/aheui.py
index b2276c8..e399dda 100644
--- a/aheui/aheui.py
+++ b/aheui/aheui.py
@@ -454,7 +454,8 @@ def prepare_compiler(contents, opt_level=2, source='code', aheuic_output=None, a
     elif source == 'asm':
         compiler.read_asm(contents.decode('utf-8'))
     else:
-        compiler.compile(contents.decode('utf-8'), add_debug_info=add_debug_info)
+        contents = contents.decode('utf-8')
+        compiler.compile(contents, add_debug_info=add_debug_info)
 
     if opt_level == 0:
         pass
diff --git a/aheui/option.py b/aheui/option.py
index 676dec0..aff6e5f 100644
--- a/aheui/option.py
+++ b/aheui/option.py
@@ -4,7 +4,7 @@
 
 import os
 from aheui._argparse import ArgumentParser
-from aheui._compat import bigint
+from aheui._compat import bigint, PY3
 from aheui.version import VERSION
 from aheui import compile
 
@@ -89,6 +89,8 @@ def open_r(filename):
         if len(args) != 1:
             os.write(2, b'aheui: error: --cmd,-c but input file found\n')
             raise SystemExit()
+        if PY3:
+            cmd = cmd.encode('utf-8')
         contents = cmd
         filename = '-'
 
@@ -100,7 +102,7 @@ def open_r(filename):
             source = 'bytecode'
         elif filename.endswith('.aheuis'):
             source = 'asm'
-        elif '\xff\xff\xff\xff' in contents:
+        elif b'\xff\xff\xff\xff' in contents:
             source = 'bytecode'
         else:
             source = 'text'