diff --git a/ecp5/cells.cc b/ecp5/cells.cc
index 4465d4e4..4a83bb30 100644
--- a/ecp5/cells.cc
+++ b/ecp5/cells.cc
@@ -211,4 +211,31 @@ void lut_to_slice(Context *ctx, CellInfo *lut, CellInfo *lc, int index)
     replace_port(lut, ctx->id("Z"), lc, ctx->id("F" + std::to_string(index)));
 }
 
+void ccu2c_to_slice(Context *ctx, CellInfo *ccu, CellInfo *lc)
+{
+    lc->params[ctx->id("MODE")] = "CCU2C";
+    lc->params[ctx->id("LUT0_INITVAL")] = str_or_default(ccu->params, ctx->id("INIT0"), "0");
+    lc->params[ctx->id("LUT1_INITVAL")] = str_or_default(ccu->params, ctx->id("INIT1"), "0");
+
+    lc->params[ctx->id("INJECT1_0")] = str_or_default(ccu->params, ctx->id("INJECT1_0"), "YES");
+    lc->params[ctx->id("INJECT1_1")] = str_or_default(ccu->params, ctx->id("INJECT1_1"), "YES");
+
+    replace_port(ccu, ctx->id("CIN"), lc, ctx->id("FCI"));
+
+    replace_port(ccu, ctx->id("A0"), lc, ctx->id("A0"));
+    replace_port(ccu, ctx->id("B0"), lc, ctx->id("B0"));
+    replace_port(ccu, ctx->id("C0"), lc, ctx->id("C0"));
+    replace_port(ccu, ctx->id("D0"), lc, ctx->id("D0"));
+
+    replace_port(ccu, ctx->id("A1"), lc, ctx->id("A1"));
+    replace_port(ccu, ctx->id("B1"), lc, ctx->id("B1"));
+    replace_port(ccu, ctx->id("C1"), lc, ctx->id("C1"));
+    replace_port(ccu, ctx->id("D1"), lc, ctx->id("D1"));
+
+    replace_port(ccu, ctx->id("S0"), lc, ctx->id("F0"));
+    replace_port(ccu, ctx->id("S1"), lc, ctx->id("F1"));
+
+    replace_port(ccu, ctx->id("COUT"), lc, ctx->id("FCO"));
+}
+
 NEXTPNR_NAMESPACE_END
diff --git a/ecp5/cells.h b/ecp5/cells.h
index b0c74ca9..d2ea5490 100644
--- a/ecp5/cells.h
+++ b/ecp5/cells.h
@@ -48,6 +48,7 @@ inline bool is_l6mux(const BaseCtx *ctx, const CellInfo *cell) { return cell->ty
 
 void ff_to_slice(Context *ctx, CellInfo *ff, CellInfo *lc, int index, bool driven_by_lut);
 void lut_to_slice(Context *ctx, CellInfo *lut, CellInfo *lc, int index);
+void ccu2c_to_slice(Context *ctx, CellInfo *ccu, CellInfo *lc);
 
 NEXTPNR_NAMESPACE_END
 
diff --git a/ecp5/pack.cc b/ecp5/pack.cc
index d2c0085b..b17f8f20 100644
--- a/ecp5/pack.cc
+++ b/ecp5/pack.cc
@@ -108,7 +108,8 @@ class Ecp5Packer
     }
 
     // Return whether or not an FF can be added to a tile (pairing checks must also be done using the fn above)
-    bool can_add_ff_to_file(const std::vector<CellInfo *> &tile_ffs, CellInfo *ff0) {
+    bool can_add_ff_to_file(const std::vector<CellInfo *> &tile_ffs, CellInfo *ff0)
+    {
         for (const auto &existing : tile_ffs) {
             if (net_or_nullptr(existing, ctx->id("CLK")) != net_or_nullptr(ff0, ctx->id("CLK")))
                 return false;
@@ -459,19 +460,19 @@ class Ecp5Packer
         return chains;
     }
 
-
     // Pack carries and set up appropriate relative constraints
-    void pack_carries() {
+    void pack_carries()
+    {
         log_info("Packing carries...\n");
-        auto chains = find_chains(ctx, [](const Context *ctx, const CellInfo *cell) {
-            return is_carry(ctx, cell);
-        }, [](const Context *ctx, const CellInfo *cell) {
-            return net_driven_by(ctx, cell->ports.at(ctx->id("CIN")).net, is_carry, ctx->id("COUT"));
-        }, [](const Context *ctx, const CellInfo *cell) {
-            return net_only_drives(ctx, cell->ports.at(ctx->id("COUT")).net, is_carry,
-                                   ctx->id("CIN"), false);
-        }, 1);
-
+        auto chains = find_chains(
+                ctx, [](const Context *ctx, const CellInfo *cell) { return is_carry(ctx, cell); },
+                [](const Context *ctx, const CellInfo *cell) {
+                    return net_driven_by(ctx, cell->ports.at(ctx->id("CIN")).net, is_carry, ctx->id("COUT"));
+                },
+                [](const Context *ctx, const CellInfo *cell) {
+                    return net_only_drives(ctx, cell->ports.at(ctx->id("COUT")).net, is_carry, ctx->id("CIN"), false);
+                },
+                1);
     }
 
     // Pack LUTs that have been paired together