diff --git a/fml/install/update_packages.py b/fml/install/update_packages.py
new file mode 100644
index 000000000..90facb5b9
--- /dev/null
+++ b/fml/install/update_packages.py
@@ -0,0 +1,64 @@
+import os, os.path, sys, csv, re, fnmatch, shutil
+from optparse import OptionParser
+
+replaced = 0
+
+def main(mcp_dir, targets):
+    global replaced
+    packages_csv = os.path.join(mcp_dir, 'conf', 'packages.csv')
+    
+    if not os.path.isfile(packages_csv):
+        print 'Could not find Packages.csv, please specify a location of a MCP directory setup with FML using --mcp-dir <path>'
+        sys.exit(1)
+    
+    pkgs = {}    
+    with open(packages_csv) as fh:
+        reader = csv.DictReader(fh)
+        for line in reader:
+            pkgs[line['class']] = line['package']
+    
+    if len(targets) == 0:
+        print 'You must specify atleast one target directory to repackage'
+        sys.exit(1)
+    
+    regnms = re.compile(r'net.minecraft.src.(\w+)')
+    total_r = 0
+    total_f = 0
+    
+    for target in targets:        
+        for path, _, filelist in os.walk(target, followlinks=True):
+            for cur_file in fnmatch.filter(filelist, '*.java'):
+                file_name = os.path.join(path, cur_file)
+                buf = ''
+                replaced = 0
+                
+                with open(file_name, 'rb') as fh:
+                    data = fh.read()
+                    def mapname(match):
+                        global replaced
+                        cls = match.group(0)
+                        tmp = cls[18:]
+                        if tmp in pkgs.keys():
+                            replaced += 1
+                            return ('%s/%s' % (pkgs[tmp], tmp)).replace('/', '.')
+                        return cls
+                    data = regnms.sub(mapname, data)
+                
+                if replaced > 0:
+                    total_r += replaced
+                    total_f += 1
+                    
+                    print '%s: %d' % (os.path.relpath(file_name), replaced)
+                    
+                    with open(file_name + '.tmp', 'wb') as fh:
+                        fh.write(data)
+                    shutil.move(file_name + '.tmp', file_name)
+                    
+    print 'Fixed %d references in %d files' % (total_r, total_f)
+    
+if __name__ == '__main__':
+    parser = OptionParser()
+    parser.add_option('-m', '--mcp-dir', action='store', dest='mcp_dir', help='MCP Directory', default='mcp')
+    options, args = parser.parse_args()
+
+    main(os.path.abspath(options.mcp_dir), args)
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