diff --git a/litex/boards/platforms/minispartan6.py b/litex/boards/platforms/minispartan6.py
index f8538ca2d..13a4cc532 100644
--- a/litex/boards/platforms/minispartan6.py
+++ b/litex/boards/platforms/minispartan6.py
@@ -118,6 +118,7 @@ class Platform(XilinxPlatform):
     default_clk_period = 1e9/32e6
 
     def __init__(self, device="xc6slx25"):
+        assert device in ["xc6slx9", "xc6slx25"]
         XilinxPlatform.__init__(self, device+"-3-ftg256", _io, _connectors)
 
     def create_programmer(self):