diff --git a/sim/fakes/_sim.py b/sim/fakes/_sim.py
index fe54b5cb31003644f8732f531fbf605cfcc6af14..b367feb54293d130bca1f53c3eb1bf6ef35b21c8 100644
--- a/sim/fakes/_sim.py
+++ b/sim/fakes/_sim.py
@@ -23,7 +23,7 @@ simpath = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
 bgpath = os.path.join(simpath, "background.png")
 background = pygame.image.load(bgpath)
 
-OLED_SIZE = screen_h // 2 if FULL_SCREEN else 240
+OLED_SIZE = int(os.environ["SIM_OLED_SIZE"])
 
 
 class Input:
diff --git a/sim/run.py b/sim/run.py
index 02212fc92853f70f98819b5e6dee91111ced3f9b..c76ee31fb08d3cf552a9569ef264d2c01cea5857 100644
--- a/sim/run.py
+++ b/sim/run.py
@@ -115,10 +115,12 @@ def sim_main():
     parser.add_argument(
         "--full-screen", dest="full_screen", action="store_true", default=False
     )
+    parser.add_argument("--oled-size", dest="oled_size", default=240)
     parser.add_argument("override_app", nargs="?")
     args = parser.parse_args()
 
     os.environ["SIM_FULL_SCREEN"] = "1" if args.full_screen else "0"
+    os.environ["SIM_OLED_SIZE"] = str(args.oled_size)
     import _sim
 
     _sim.SCREENSHOT = args.screenshot