diff --git a/Main.py b/Main.py
index 6d416c17..17f16ef0 100644
--- a/Main.py
+++ b/Main.py
@@ -246,7 +246,7 @@ def main(args, seed=None):
         return player, team, bytes(rom.name).decode()
 
     pool = concurrent.futures.ThreadPoolExecutor()
-
+    multidata_task = None
     if not args.suppress_rom:
 
         rom_futures = []
@@ -302,11 +302,13 @@ def main(args, seed=None):
             with open(output_path('%s.multidata' % outfilebase), 'wb') as f:
                 f.write(multidata)
 
-        pool.submit(write_multidata, rom_futures)
+        multidata_task = pool.submit(write_multidata, rom_futures)
 
     if not args.skip_playthrough:
         logger.info('Calculating playthrough.')
         create_playthrough(world)
+    if multidata_task:
+        multidata_task.result()  # retrieve exception if one exists
     pool.shutdown()  # wait for all queued tasks to complete
     if args.create_spoiler:  # needs spoiler.hashes to be filled, that depend on rom_futures being done
         world.spoiler.to_file(output_path('%s_Spoiler.txt' % outfilebase))
diff --git a/ModuleUpdate.py b/ModuleUpdate.py
index e8abef64..4093d537 100644
--- a/ModuleUpdate.py
+++ b/ModuleUpdate.py
@@ -10,7 +10,8 @@ def update_command():
     subprocess.call([sys.executable, '-m', 'pip', 'install', '-r', 'requirements.txt', '--upgrade'])
 
 
-naming_specialties = {"PyYAML": "yaml"}  # PyYAML is imported as the name yaml
+naming_specialties = {"PyYAML": "yaml",  # PyYAML is imported as the name yaml
+                      "maseya-z3pr": "maseya"}
 
 
 def update():
diff --git a/Rom.py b/Rom.py
index 6e5b17e3..fa16109d 100644
--- a/Rom.py
+++ b/Rom.py
@@ -25,7 +25,10 @@ from Items import ItemFactory
 from EntranceShuffle import door_addresses
 import Patch
 
-
+try:
+    from maseya import z3pr
+except:
+    z3pr = None
 
 class LocalRom(object):
 
@@ -1477,16 +1480,33 @@ def apply_rom_settings(rom, beep, color, quickswap, fastmenu, disable_music, spr
     if sprite is not None:
         write_sprite(rom, sprite)
 
+    # reset palette if it was adjusted already
     default_ow_palettes(rom)
-    if ow_palettes == 'random':
-        randomize_ow_palettes(rom, local_random)
-    elif ow_palettes == 'blackout':
-        blackout_ow_palettes(rom)
-
     default_uw_palettes(rom)
-    if uw_palettes == 'random':
-        randomize_uw_palettes(rom, local_random)
-    elif uw_palettes == 'blackout':
+
+    if z3pr:
+        options = {
+            "randomize_dungeon": uw_palettes == 'random',
+            "randomize_overworld": ow_palettes == 'random'
+        }
+        if any(options.values()):
+            ColorF = z3pr.ColorF
+
+            def next_color():
+                return ColorF(local_random.random(), local_random.random(), local_random.random())
+
+            z3pr.randomize(rom.buffer, "maseya", next_color, options)
+    else:
+        logging.warning("Could not find z3pr palette shuffle. "
+                        "If you want improved palette shuffling please install the maseya-z3pr package.")
+        if ow_palettes == 'random':
+            randomize_ow_palettes(rom, local_random)
+        if uw_palettes == 'random':
+            randomize_uw_palettes(rom, local_random)
+
+    if ow_palettes == 'blackout':
+        blackout_ow_palettes(rom)
+    if uw_palettes == 'blackout':
         blackout_uw_palettes(rom)
 
     if isinstance(rom, LocalRom):