diff --git a/build_library/cgpt.py b/build_library/cgpt.py
index a8280e3e54..31ef360f35 100755
--- a/build_library/cgpt.py
+++ b/build_library/cgpt.py
@@ -29,25 +29,25 @@ def LoadPartitionConfig(filename):
   """
 
   if not os.path.exists(filename):
-    raise ConfigNotFound("Partition config %s was not found!" % filename)
+    raise ConfigNotFound('Partition config %s was not found!' % filename)
   with open(filename) as f:
     config = json.load(f)
     f.close()
 
-  metadata = config["metadata"]
-  metadata["block_size"] = int(metadata["block_size"])
+  metadata = config['metadata']
+  metadata['block_size'] = int(metadata['block_size'])
 
-  for layout_name, layout in config["layouts"].items():
+  for layout_name, layout in config['layouts'].items():
     for part in layout:
-      part["blocks"] = int(part["blocks"])
-      part["bytes"] = part["blocks"] * metadata["block_size"]
+      part['blocks'] = int(part['blocks'])
+      part['bytes'] = part['blocks'] * metadata['block_size']
 
-      if "fs_blocks" in part:
-        part["fs_blocks"] = int(part["fs_blocks"])
-        part["fs_bytes"] = part["fs_blocks"] * metadata["fs_block_size"]
+      if 'fs_blocks' in part:
+        part['fs_blocks'] = int(part['fs_blocks'])
+        part['fs_bytes'] = part['fs_blocks'] * metadata['fs_block_size']
 
-        if part["fs_bytes"] > part["bytes"]:
-          raise InvalidLayout("Filesystem may not be larger than partition")
+        if part['fs_bytes'] > part['bytes']:
+          raise InvalidLayout('Filesystem may not be larger than partition')
 
   return config
 
@@ -63,28 +63,28 @@ def GetTableTotals(config, partitions):
   """
 
   ret = {
-    "expand_count": 0,
-    "expand_min": 0,
-    "block_count": START_SECTOR * config["metadata"]["block_size"]
+    'expand_count': 0,
+    'expand_min': 0,
+    'block_count': START_SECTOR * config['metadata']['block_size']
   }
 
   # Total up the size of all non-expanding partitions to get the minimum
   # required disk size.
   for partition in partitions:
-    if "features" in partition and "expand" in partition["features"]:
-      ret["expand_count"] += 1
-      ret["expand_min"] += partition["blocks"]
+    if 'features' in partition and 'expand' in partition['features']:
+      ret['expand_count'] += 1
+      ret['expand_min'] += partition['blocks']
     else:
-      ret["block_count"] += partition["blocks"]
+      ret['block_count'] += partition['blocks']
 
   # At present, only one expanding partition is permitted.
   # Whilst it'd be possible to have two, we don't need this yet
   # and it complicates things, so it's been left out for now.
-  if ret["expand_count"] > 1:
-    raise InvalidLayout("1 expand partition allowed, %d requested"
-                        % ret["expand_count"])
+  if ret['expand_count'] > 1:
+    raise InvalidLayout('1 expand partition allowed, %d requested'
+                        % ret['expand_count'])
 
-  ret["min_disk_size"] = ret["block_count"] + ret["expand_min"]
+  ret['min_disk_size'] = ret['block_count'] + ret['expand_min']
 
   return ret
 
@@ -102,14 +102,14 @@ def GetPartitionTable(config, image_type):
     Object representing a selected partition table
   """
 
-  partitions = config["layouts"]["base"]
+  partitions = config['layouts']['base']
 
-  if image_type != "base":
-    for partition_t in config["layouts"][image_type]:
+  if image_type != 'base':
+    for partition_t in config['layouts'][image_type]:
       for partition in partitions:
-        if partition["type"] == "blank" or partition_t["type"] == "blank":
+        if partition['type'] == 'blank' or partition_t['type'] == 'blank':
           continue
-        if partition_t["num"] == partition["num"]:
+        if partition_t['num'] == partition['num']:
           for k, v in partition_t.items():
             partition[k] = v
 
@@ -123,14 +123,14 @@ def GetScriptShell():
     A string containg the skeleton script
   """
 
-  script_shell_path = os.path.join(os.path.dirname(__file__), "cgpt_shell.sh")
-  with open(script_shell_path, "r") as f:
+  script_shell_path = os.path.join(os.path.dirname(__file__), 'cgpt_shell.sh')
+  with open(script_shell_path, 'r') as f:
     script_shell = "".join(f.readlines())
     f.close()
 
   # Before we return, insert the path to this tool so somebody reading the
   # script later can tell where it was generated.
-  script_shell = script_shell.replace("@SCRIPT_GENERATOR@", script_shell_path)
+  script_shell = script_shell.replace('@SCRIPT_GENERATOR@', script_shell_path)
 
   return script_shell
 
@@ -148,50 +148,49 @@ def WriteLayoutFunction(sfile, func_name, image_type, config):
   partitions = GetPartitionTable(config, image_type)
   partition_totals = GetTableTotals(config, partitions)
 
-  sfile.write("%s() {\ncreate_image $1 %d %s\n" % (
-  func_name, partition_totals["min_disk_size"],
-  config["metadata"]["block_size"]))
+  sfile.write('%s() {\ncreate_image $1 %d %s\n' % (
+      func_name, partition_totals['min_disk_size'],
+      config['metadata']['block_size']))
 
-  sfile.write("CURR=%d\n" % START_SECTOR)
-  sfile.write("$GPT create $1\n")
+  sfile.write('CURR=%d\n' % START_SECTOR)
+  sfile.write('$GPT create $1\n')
 
   # Pass 1: Set up the expanding partition size.
   for partition in partitions:
-    partition["var"] = partition["blocks"]
-    if partition["type"] != "blank":
+    partition['var'] = partition['blocks']
+    if partition['type'] != 'blank':
 
-      if partition["num"] == 1:
-        if "features" in partition and "expand" in partition["features"]:
-          sfile.write("if [ -b $1 ]; then\n")
-          sfile.write("STATEFUL_SIZE=$(( $(numsectors $1) - %d))\n" %
-            partition_totals["block_count"])
-          sfile.write("else\n")
-          sfile.write("STATEFUL_SIZE=%s\n" % partition["blocks"])
-          sfile.write("fi\n")
-          partition["var"] = "$STATEFUL_SIZE"
+      if partition['num'] == 1:
+        if 'features' in partition and 'expand' in partition['features']:
+          sfile.write('if [ -b $1 ]; then\n')
+          sfile.write('STATEFUL_SIZE=$(( $(numsectors $1) - %d))\n' %
+            partition_totals['block_count'])
+          sfile.write('else\n')
+          sfile.write('STATEFUL_SIZE=%s\n' % partition['blocks'])
+          sfile.write('fi\n')
+          partition['var'] = '$STATEFUL_SIZE'
 
-
-  sfile.write("STATEFUL_SIZE=$((STATEFUL_SIZE-(STATEFUL_SIZE %% %d)))\n" %
-    config["metadata"]["fs_block_size"])
+  sfile.write('STATEFUL_SIZE=$((STATEFUL_SIZE-(STATEFUL_SIZE %% %d)))\n' %
+    config['metadata']['fs_block_size'])
 
   # Pass 2: Write out all the cgpt add commands.
   for partition in partitions:
-    if partition["type"] != "blank":
-      sfile.write("$GPT add -i %d -b $CURR -s %s -t %s -l %s $1 && " % (
-        partition["num"], str(partition["var"]), partition["type"],
-        partition["label"]))
+    if partition['type'] != 'blank':
+      sfile.write('$GPT add -i %d -b $CURR -s %s -t %s -l %s $1 && ' % (
+          partition['num'], str(partition['var']), partition['type'],
+          partition['label']))
 
     # Increment the CURR counter ready for the next partition.
-    sfile.write("CURR=$(( $CURR + %s ))\n" % partition["var"])
+    sfile.write('CURR=$(( $CURR + %s ))\n' % partition['var'])
 
   # Set default priorities on kernel partitions
-  sfile.write("$GPT add -i 2 -S 0 -T 15 -P 15 $1\n")
-  sfile.write("$GPT add -i 4 -S 0 -T 15 -P 0 $1\n")
-  sfile.write("$GPT add -i 6 -S 0 -T 15 -P 0 $1\n")
+  sfile.write('$GPT add -i 2 -S 0 -T 15 -P 15 $1\n')
+  sfile.write('$GPT add -i 4 -S 0 -T 15 -P 0 $1\n')
+  sfile.write('$GPT add -i 6 -S 0 -T 15 -P 0 $1\n')
 
-  sfile.write("$GPT boot -p -b $2 -i 12 $1\n")
-  sfile.write("$GPT show $1\n")
-  sfile.write("}\n")
+  sfile.write('$GPT boot -p -b $2 -i 12 $1\n')
+  sfile.write('$GPT show $1\n')
+  sfile.write('}\n')
 
 
 def GetPartitionByNumber(partitions, num):
@@ -204,12 +203,12 @@ def GetPartitionByNumber(partitions, num):
     An object for the selected partition
   """
   for partition in partitions:
-    if partition["type"] == "blank":
+    if partition['type'] == 'blank':
       continue
-    if partition["num"] == int(num):
+    if partition['num'] == int(num):
       return partition
 
-  raise PartitionNotFound("Partition not found")
+  raise PartitionNotFound('Partition not found')
 
 
 def WritePartitionScript(image_type, layout_filename, sfilename):
@@ -223,12 +222,12 @@ def WritePartitionScript(image_type, layout_filename, sfilename):
 
   config = LoadPartitionConfig(layout_filename)
 
-  sfile = open(sfilename, "w")
+  sfile = open(sfilename, 'w')
   script_shell = GetScriptShell()
   sfile.write(script_shell)
 
-  WriteLayoutFunction(sfile, "write_base_table", "base", config)
-  WriteLayoutFunction(sfile, "write_partition_table", image_type, config)
+  WriteLayoutFunction(sfile, 'write_base_table', 'base', config)
+  WriteLayoutFunction(sfile, 'write_partition_table', image_type, config)
 
   sfile.close()
 
@@ -243,7 +242,7 @@ def GetBlockSize(layout_filename):
   """
 
   config = LoadPartitionConfig(layout_filename)
-  return config["metadata"]["block_size"]
+  return config['metadata']['block_size']
 
 
 def GetFilesystemBlockSize(layout_filename):
@@ -258,7 +257,7 @@ def GetFilesystemBlockSize(layout_filename):
   """
 
   config = LoadPartitionConfig(layout_filename)
-  return config["metadata"]["fs_block_size"]
+  return config['metadata']['fs_block_size']
 
 
 def GetPartitionSize(image_type, layout_filename, num):
@@ -276,7 +275,7 @@ def GetPartitionSize(image_type, layout_filename, num):
   partitions = GetPartitionTable(config, image_type)
   partition = GetPartitionByNumber(partitions, num)
 
-  return partition["bytes"]
+  return partition['bytes']
 
 
 def GetFilesystemSize(image_type, layout_filename, num):
@@ -296,10 +295,10 @@ def GetFilesystemSize(image_type, layout_filename, num):
   partitions = GetPartitionTable(config, image_type)
   partition = GetPartitionByNumber(partitions, num)
 
-  if "fs_bytes" in partition:
-    return partition["fs_bytes"]
+  if 'fs_bytes' in partition:
+    return partition['fs_bytes']
   else:
-    return partition["bytes"]
+    return partition['bytes']
 
 
 def GetLabel(image_type, layout_filename, num):
@@ -310,17 +309,17 @@ def GetLabel(image_type, layout_filename, num):
     layout_filename: Path to partition configuration file
     num: Number of the partition you want to read from
   Returns:
-    Label of selected partition, or "UNTITLED" if none specified
+    Label of selected partition, or 'UNTITLED' if none specified
   """
 
   config = LoadPartitionConfig(layout_filename)
   partitions = GetPartitionTable(config, image_type)
   partition = GetPartitionByNumber(partitions, num)
 
-  if "label" in partition:
-    return partition["label"]
+  if 'label' in partition:
+    return partition['label']
   else:
-    return "UNTITLED"
+    return 'UNTITLED'
 
 
 def DoDebugOutput(image_type, layout_filename):
@@ -337,75 +336,76 @@ def DoDebugOutput(image_type, layout_filename):
   partitions = GetPartitionTable(config, image_type)
 
   for partition in partitions:
-    if partition["bytes"] < 1024 * 1024:
-      size = "%d bytes" % partition["bytes"]
+    if partition['bytes'] < 1024 * 1024:
+      size = '%d bytes' % partition['bytes']
     else:
-      size = "%d MB" % (partition["bytes"] / 1024 / 1024)
-    if "label" in partition:
-      if "fs_bytes" in partition:
-        if partition["fs_bytes"] < 1024 * 1024:
-          fs_size = "%d bytes" % partition["fs_bytes"]
+      size = '%d MB' % (partition['bytes'] / 1024 / 1024)
+    if 'label' in partition:
+      if 'fs_bytes' in partition:
+        if partition['fs_bytes'] < 1024 * 1024:
+          fs_size = '%d bytes' % partition['fs_bytes']
         else:
-          fs_size = "%d MB" % (partition["fs_bytes"] / 1024 / 1024)
-        print "%s - %s/%s" % (partition["label"], fs_size, size)
+          fs_size = '%d MB' % (partition['fs_bytes'] / 1024 / 1024)
+        print '%s - %s/%s' % (partition['label'], fs_size, size)
       else:
-        print "%s - %s" % (partition["label"], size)
+        print '%s - %s' % (partition['label'], size)
     else:
-      print "blank - %s" %  size
+      print 'blank - %s' %  size
 
 
 def main(argv):
   action_map = {
-    "write": {
-      "argc": 4,
-      "usage": "<image_type> <partition_config_file> <script_file>",
-      "func": WritePartitionScript
+    'write': {
+      'argc': 4,
+      'usage': '<image_type> <partition_config_file> <script_file>',
+      'func': WritePartitionScript,
     },
-    "readblocksize": {
-      "argc": 2,
-      "usage": "<partition_config_file>",
-      "func": GetBlockSize
+    'readblocksize': {
+      'argc': 2,
+      'usage': '<partition_config_file>',
+      'func': GetBlockSize,
     },
-    "readfsblocksize": {
-      "argc": 2,
-      "usage": "<partition_config_file>",
-      "func": GetFilesystemBlockSize
+    'readfsblocksize': {
+      'argc': 2,
+      'usage': '<partition_config_file>',
+      'func': GetFilesystemBlockSize,
     },
-    "readpartsize": {
-      "argc": 4,
-      "usage": "<image_type> <partition_config_file> <partition_num>",
-      "func": GetPartitionSize
+    'readpartsize': {
+      'argc': 4,
+      'usage': '<image_type> <partition_config_file> <partition_num>',
+      'func': GetPartitionSize,
     },
-    "readfssize": {
-      "argc": 4,
-      "usage": "<image_type> <partition_config_file> <partition_num>",
-      "func": GetFilesystemSize
+    'readfssize': {
+      'argc': 4,
+      'usage': '<image_type> <partition_config_file> <partition_num>',
+      'func': GetFilesystemSize,
     },
-    "readlabel": {
-      "argc": 4,
-      "usage": "<image_type> <partition_config_file> <partition_num>",
-      "func": GetLabel
+    'readlabel': {
+      'argc': 4,
+      'usage': '<image_type> <partition_config_file> <partition_num>',
+      'func': GetLabel,
     },
-    "debug": {
-      "argc": 3,
-      "usage": "<image_type> <partition_config_file>",
-      "func": DoDebugOutput
+    'debug': {
+      'argc': 3,
+      'usage': '<image_type> <partition_config_file>',
+      'func': DoDebugOutput,
     }
   }
 
   if len(sys.argv) < 2 or sys.argv[1] not in action_map:
-    print "Usage: %s <action>\n" % sys.argv[0]
-    print "Valid actions are:"
+    print 'Usage: %s <action>\n' % sys.argv[0]
+    print 'Valid actions are:'
     for action in action_map:
-      print "  %s %s" % (action, action_map[action]["usage"])
+      print '  %s %s' % (action, action_map[action]['usage'])
     sys.exit(1)
   else:
     action_name = sys.argv[1]
     action = action_map[action_name]
-    if action["argc"] == len(sys.argv) - 1:
-      print action["func"](*sys.argv[2:])
+    if action['argc'] == len(sys.argv) - 1:
+      print action['func'](*sys.argv[2:])
     else:
-      sys.exit("Usage: %s %s %s" % (sys.argv[0], sys.argv[1], action["usage"]))
+      sys.exit('Usage: %s %s %s' % (sys.argv[0], sys.argv[1], action['usage']))
 
-if __name__ == "__main__":
+
+if __name__ == '__main__':
   main(sys.argv)