diff --git a/litex_boards/platforms/sipeed_tang_primer_20k.py b/litex_boards/platforms/sipeed_tang_primer_20k.py
index 6bab707d..2d320e86 100644
--- a/litex_boards/platforms/sipeed_tang_primer_20k.py
+++ b/litex_boards/platforms/sipeed_tang_primer_20k.py
@@ -135,10 +135,10 @@ _connectors = [
 
 _dock_io = [
     # Leds
-    ("led", 0,  Pins( "CARD1:44"), IOStandard("LVCMOS18")),
-    ("led", 1,  Pins( "CARD1:46"), IOStandard("LVCMOS18")),
-    ("led", 3,  Pins( "CARD1:40"), IOStandard("LVCMOS18")),
-    ("led", 2,  Pins( "CARD1:42"), IOStandard("LVCMOS18")),
+    ("led", 0,  Pins( "CARD1:44"), IOStandard("LVCMOS18")), # CHECKME: Should be LVCMOS33.
+    ("led", 1,  Pins( "CARD1:46"), IOStandard("LVCMOS18")), # CHECKME: Should be LVCMOS33.
+    ("led", 3,  Pins( "CARD1:40"), IOStandard("LVCMOS18")), # CHECKME: Should be LVCMOS33.
+    ("led", 2,  Pins( "CARD1:42"), IOStandard("LVCMOS18")), # CHECKME: Should be LVCMOS33.
     ("led", 4,  Pins( "CARD1:98"), IOStandard("LVCMOS33")),
     ("led", 5,  Pins("CARD1:136"), IOStandard("LVCMOS33")),