diff --git a/BaseTools/Source/Python/Common/Misc.py b/BaseTools/Source/Python/Common/Misc.py
index ad556710802e..4be7957138a5 100755
--- a/BaseTools/Source/Python/Common/Misc.py
+++ b/BaseTools/Source/Python/Common/Misc.py
@@ -1635,7 +1635,7 @@ def __init__(self, PeFile):
         ByteArray = array.array('B')
         ByteArray.fromfile(PeObject, 4)
         # PE signature should be 'PE\0\0'
-        if ByteArray.tostring() != b'PE\0\0':
+        if ByteArray.tolist() != [ord('P'), ord('E'), 0, 0]:
             self.ErrorInfo = self.FileName + ' has no valid PE signature PE00'
             return
 
diff --git a/BaseTools/Source/Python/AutoGen/UniClassObject.py b/BaseTools/Source/Python/AutoGen/UniClassObject.py
index b2895f7e5c63..883c2356e0ca 100644
--- a/BaseTools/Source/Python/AutoGen/UniClassObject.py
+++ b/BaseTools/Source/Python/AutoGen/UniClassObject.py
@@ -152,7 +152,7 @@ def encode(self, input, errors='strict'):
 
 TheUcs2Codec = Ucs2Codec()
 def Ucs2Search(name):
-    if name == 'ucs-2':
+    if name in ['ucs-2', 'ucs_2']:
         return codecs.CodecInfo(
             name=name,
             encode=TheUcs2Codec.encode,