diff --git a/litex_boards/platforms/colorlight_5a_75b.py b/litex_boards/platforms/colorlight_5a_75b.py
index 0cf0219..6564bd2 100644
--- a/litex_boards/platforms/colorlight_5a_75b.py
+++ b/litex_boards/platforms/colorlight_5a_75b.py
@@ -19,6 +19,15 @@ _io_v6_1 = [ # Documented by @smunaut
     # btn
     ("user_btn_n", 0, Pins("R16"), IOStandard("LVCMOS33")),
 
+    # serial
+    ("serial", 0,
+        Subsignal("tx", Pins("U16")), # led (J19 DATA_LED-)
+        Subsignal("rx", Pins("R16")), # btn (J19 KEY+)
+        # It seems there's some capacitance on the KEY+ pin, so bigger baudrates
+        # may not work
+        IOStandard("LVCMOS33")
+    ),
+
     # spi flash (GD25Q16CSIG)
     ("spiflash", 0,
         Subsignal("cs_n", Pins("R2")),
@@ -68,8 +77,8 @@ _io_v6_1 = [ # Documented by @smunaut
     ),
 
     ("eth_clocks", 1,
-        Subsignal("tx", Pins("")),
-        Subsignal("rx", Pins("")),
+        Subsignal("tx", Pins("U19")),
+        Subsignal("rx", Pins("L19")),
         IOStandard("LVCMOS33")
     ),
     ("eth", 1,