diff --git a/nmigen_boards/colorlight_i5_r7_0_ext_board.py b/nmigen_boards/colorlight_i5_r7_0_ext_board.py
new file mode 100644
index 00000000..c18b9585
--- /dev/null
+++ b/nmigen_boards/colorlight_i5_r7_0_ext_board.py
@@ -0,0 +1,135 @@
+import os
+import subprocess
+
+from nmigen.build import *
+from nmigen.vendor.lattice_ecp5 import *
+from resources import *
+
+
+__all__ = ["Colorlighti5R70ExtensionBoardPlatform"]
+
+
+class Colorlighti5R70ExtensionBoardPlatform(LatticeECP5Platform):
+    """
+    The Colorlight i5 r7.0 is often paired with an extension develpmnet board
+    which provides an ample set of I/O.
+
+    Official documentation of Colorlight i5 r7.0 and extension board:
+    https://github.com/wuxx/Colorlight-FPGA-Projects
+
+    The extension board schematic:
+    https://github.com/wuxx/Colorlight-FPGA-Projects/blob/master/schematic/i5_v6.0-extboard.pdf
+
+    Tom Verbeure FPGA pin to connector on extension board mapping diagram:
+    https://tomverbeure.github.io/assets/colorlight_i5/colorlight_i5_ext_board_pin_mapping.pdf
+    """
+
+    device                 = "LFE5U-25F"
+    package                = "BG381"
+    speed                  = "6"
+    default_clk            = "clk25"
+
+    resources = [
+        Resource("clk25", 0, Pins("P3", dir="i"), Clock(25e6), Attrs(IO_TYPE="LVCMOS33")),
+
+        *LEDResources(pins="U16", invert = True, attrs=Attrs(IO_TYPE="LVCMOS33", DRIVE="4")),
+
+        UARTResource(0,
+            tx="H18",
+            rx="J17",
+            attrs=Attrs(IO_TYPE="LVCMOS33")
+        ),
+
+        Resource("hdmi_tx", 0,
+            Subsignal("clk", DiffPairs("J19", "K19", dir="o"),
+                Attrs(IOSTANDARD="TMDS_33")),
+            Subsignal("d",   DiffPairs("G19 E20 C20", "H20 F19 D19", dir="o"),
+                Attrs(IOSTANDARD="TMDS_33")),
+            Attrs(IOSTANDARD="LVCMOS33")),
+
+        *SPIFlashResources(0,
+            cs_n="R2",
+            clk="U3",
+            copi="W2",
+            cipo="V2",
+            attrs=Attrs(IO_TYPE="LVCMOS33")
+        ),
+
+        # EtronTech EM638325-6H 2M x 32bit SDRAM, 166MHz
+        SDRAMResource(0,
+            clk="B9", we_n="A10", cas_n="A9", ras_n="B10",
+            ba="B11 C8", a="B13 C14 A16 A17 B16 B15 A14 A13 A12 A11 B12",
+            dq="B6  A5 A6  A7  C7  B8  B5 A8  D8  D7  E8  D6  C6  D5  E7  C5 "
+               "C10 D9 E11 D11 C11 D12 E9 C12 E14 C15 E13 D15 E12 B17 D14 D13",
+            attrs=Attrs(PULLMODE="NONE", DRIVE="4", SLEWRATE="FAST", IO_TYPE="LVCMOS33")
+        ),
+
+        # Broadcom B50612D Gigabit Ethernet Transceiver
+        Resource("eth_rgmii", 0,
+            Subsignal("rst",     PinsN("P4", dir="o")),
+            Subsignal("mdc",     Pins("N5", dir="o")),
+            Subsignal("mdio",    Pins("P5", dir="io")),
+            Subsignal("tx_clk",  Pins("U19", dir="o")),
+            Subsignal("tx_ctl",  Pins("P19", dir="o")),
+            Subsignal("tx_data", Pins("U20 T19 T20 R20", dir="o")),
+            Subsignal("rx_clk",  Pins("L19", dir="i")),
+            Subsignal("rx_ctl",  Pins("M20", dir="i")),
+            Subsignal("rx_data", Pins("P20 N19 N20 M19", dir="i")),
+            Attrs(IO_TYPE="LVCMOS33")
+        ),
+
+        # Broadcom B50612D Gigabit Ethernet Transceiver
+        Resource("eth_rgmii", 1,
+            Subsignal("rst",     PinsN("P4", dir="o")),
+            Subsignal("mdc",     Pins("N5", dir="o")),
+            Subsignal("mdio",    Pins("P5", dir="io")),
+            Subsignal("tx_clk",  Pins("G1", dir="o")),
+            Subsignal("tx_ctl",  Pins("K1", dir="o")),
+            Subsignal("tx_data", Pins("G2 H1 J1 J3", dir="o")),
+            Subsignal("rx_clk",  Pins("H2", dir="i")),
+            Subsignal("rx_ctl",  Pins("P2", dir="i")),
+            Subsignal("rx_data", Pins("K2 L1 N1 P1", dir="i")),
+            Attrs(IO_TYPE="LVCMOS33")
+        ),
+    ]
+
+    connectors = [
+        Connector("pmod", 0, "M17 R17 T18 K18 - - P17 R18 C18 U16 - -"),  # P2A
+        Connector("pmod", 1, "G20 K20 L20 N18 - - J20 L18 M18 N17 - -"),  # P2B
+        Connector("pmod", 2, "A18 A19 B19 D20 - - C17 B18 B20 F20 - -"),  # P3A
+        Connector("pmod", 3, "E2  D2  B1  A12 - - D1  C1  C2  E3  - -"),  # P3B
+        Connector("pmod", 4, "H3  F3  E4  E1  - - H4  G3  F1  F2  - -"),  # P4A
+        Connector("pmod", 5, "-   B2  K4  A2  - - -   E19 B3  K5  - -"),  # P4B
+        Connector("pmod", 6, "D17 D16 E6  F4  - - D18 G5  F5  E5  - -"),  # P5A
+        Connector("pmod", 7, "H18 G18 F18 E18 - - J17 H17 H16 G16 - -"),  # P5B
+        Connector("pmod", 8, "N4  L4  P16 J18 - - R3  M4  L5  J16 - -"),  # P6A
+        Connector("pmod", 9, "T1  Y2  V1  N2  - - R1  U1  W1  M1  - -"),  # P6B
+
+        Connector("gpio", 0, {
+            "P2_7" : "U18", "P2_9" : "P18", "P2_22" : "U17", "P2_24" : "T17", # P2
+            "P3_7" : "C4" , "P3_9" : "C3" , "P3_22" : "B4" , "P3_24" : "D3" , # P3
+            "P4_7" : "H5" , "P4_9" : "J5" , "P4_22" : "K3" , "P4_24" : "J4" , # P4
+            "P5_7" : "E17", "P5_9" : "E16", "P5_22" : "F17", "P5_24" : "E16", # P5
+            "P6_7" : "T3" , "P6_9" : "T2" , "P6_22" : "N3" , "P6_24" : "M3" , # P6
+        }),
+    ]
+
+    @property
+    def required_tools(self):
+        return super().required_tools + [
+            "openFPGALoader"
+        ]
+
+    def toolchain_prepare(self, fragment, name, **kwargs):
+        overrides = dict(ecppack_opts="--compress")
+        overrides.update(kwargs)
+        return super().toolchain_prepare(fragment, name, **overrides)
+
+    def toolchain_program(self, products, name):
+        tool = os.environ.get("OPENFPGALOADER", "openFPGALoader")
+        with products.extract("{}.bit".format(name)) as bitstream_filename:
+            subprocess.run([tool, "-c", "cmsisdap", "-m", bitstream_filename])
+
+if __name__ == "__main__":
+    from test.blinky import *
+    Colorlighti5R70ExtensionBoardPlatform().build(Blinky(), do_program=True)