diff --git a/flow/Makefile b/flow/Makefile
index 212474ba84..ce6a8ef3c9 100644
--- a/flow/Makefile
+++ b/flow/Makefile
@@ -274,6 +274,7 @@ do-auto-memories: $(RESULTS_DIR)/memories_inferred.json
 	mkdir -p $(RESULTS_DIR)
 	$(PYTHON_EXE) $(SCRIPTS_DIR)/memories/gen_memories.py \
 	  --platform $(PLATFORM) \
+	  --top $(DESIGN_NAME) \
 	  --yosys-json $(RESULTS_DIR)/memories_inferred.json \
 	  --out-dir $(RESULTS_DIR)/memories \
 	  --json $(RESULTS_DIR)/memories.json \
diff --git a/flow/scripts/memories/detect.py b/flow/scripts/memories/detect.py
index d2b7364529..2343350429 100644
--- a/flow/scripts/memories/detect.py
+++ b/flow/scripts/memories/detect.py
@@ -112,8 +112,14 @@ def _clock_enable_bits(val, ports: int) -> str:
     return val
 
 
-def scan_yosys_json(data: dict | str | Path) -> list[schema.Memory]:
-    """Extract memory modules from a Yosys netlist JSON output ($mem_v2 cells)."""
+def scan_yosys_json(
+    data: dict | str | Path, top: str | None = None
+) -> list[schema.Memory]:
+    """Extract memory modules from a Yosys netlist JSON output ($mem_v2 cells).
+
+    `top` is the design's top module; slang's per-instance module names
+    are cut back to their definition with it (see definition_name).
+    """
     if isinstance(data, (str, Path)):
         data = json.loads(Path(data).read_text())
 
@@ -122,6 +128,13 @@ def scan_yosys_json(data: dict | str | Path) -> list[schema.Memory]:
 
     for mod_name, mod_info in modules.items():
         clean_mod_name = mod_name[1:] if mod_name.startswith("\\") else mod_name
+        # slang's --keep-hierarchy elaborates one module per instance and
+        # names it `<definition>$<instance path>`; the flow blackboxes by
+        # definition (`--blackboxed-module <definition>` is what the
+        # frontend honours, and the black box it imports has the
+        # definition's type), so the memory is named for the definition
+        # and its copies collapse into one entry below.
+        clean_mod_name = definition_name(clean_mod_name, top)
         cells = mod_info.get("cells", {})
         mem_cells = [
             n for n, c in cells.items() if c.get("type", "") in ("$mem_v2", "$mem")
@@ -289,4 +302,56 @@ def scan_yosys_json(data: dict | str | Path) -> list[schema.Memory]:
             )
             out.append(mem)
 
-    return out
+    return dedupe(out)
+
+
+def definition_name(module: str, top: str | None) -> str:
+    """`array_64x114$top.u0` -> `array_64x114` for top module `top`.
+
+    slang's instance path starts at the top module, so the name is cut
+    where `$<top>.` begins, not at the first `$`: a definition may have a
+    `$` of its own (`my$ram$top.u0` is `my$ram`). Any other name, yosys's
+    own `$paramod\\...` names among them, is returned unchanged.
+    """
+    if top:
+        i = module.find(f"${top}.")
+        if i > 0:
+            return module[:i]
+    return module
+
+
+def dedupe(memories: list[schema.Memory]) -> list[schema.Memory]:
+    """One entry per name; copies must agree on shape and pins.
+
+    The copies are one definition elaborated per instance, so they agree
+    unless the definition is parameterised on the memory's shape -- and
+    then one liberty view per definition cannot serve them, which is an
+    error rather than a silent pick.
+    """
+
+    def shape(m):
+        return (
+            m.rows,
+            m.bits,
+            m.read_ports,
+            m.write_ports,
+            m.rw_ports,
+            m.mask_lanes,
+            m.comb_read_ports,
+            m.port_convention,
+            tuple(m.pins),
+        )
+
+    by_name: dict[str, schema.Memory] = {}
+    for m in memories:
+        first = by_name.get(m.name)
+        if first is None:
+            by_name[m.name] = m
+        elif shape(first) != shape(m):
+            raise ValueError(
+                f"memory {m.name}: two elaborations differ in shape "
+                f"({first.rows}x{first.bits} against {m.rows}x{m.bits}, or in "
+                "ports); a definition parameterised on its memory cannot be "
+                "one macro"
+            )
+    return list(by_name.values())
diff --git a/flow/scripts/memories/detect_test.py b/flow/scripts/memories/detect_test.py
index 9965ea9f4f..c1f70e0ef7 100644
--- a/flow/scripts/memories/detect_test.py
+++ b/flow/scripts/memories/detect_test.py
@@ -157,6 +157,44 @@ def test_one_memory_per_module_is_named_after_the_module(self):
         mems = detect.scan_yosys_json(yosys_json)
         self.assertEqual(sorted(m.name for m in mems), ["array_256x66", "array_64x114"])
 
+    def test_slang_uniquified_copies_collapse_to_the_definition(self):
+        # slang --keep-hierarchy names a module per instance; the flow
+        # blackboxes the definition, so that is the memory's name and its
+        # copies are one entry
+        yosys_json = {
+            "modules": {
+                "\\array_64x114$top.t0.u0": _firtool_rw_module(),
+                "\\array_64x114$top.t0.u1": _firtool_rw_module(),
+                "\\array_256x66$top.t1.u0": _firtool_rw_module(256, 66, 1),
+            }
+        }
+        mems = detect.scan_yosys_json(yosys_json, top="top")
+        self.assertEqual(sorted(m.name for m in mems), ["array_256x66", "array_64x114"])
+        by = {m.name: m for m in mems}
+        self.assertEqual(by["array_64x114"].behavioral_model["module"], "array_64x114")
+
+    def test_definition_name_is_cut_where_the_instance_path_starts(self):
+        name = detect.definition_name
+        # read_slang names modules this way: a definition with a `$` of its
+        # own, an escaped one starting with a digit, a single instance
+        self.assertEqual(name("my$ram$top2.u2", "top2"), "my$ram")
+        self.assertEqual(name("1d_ram$top2.u0", "top2"), "1d_ram")
+        self.assertEqual(name("ram$top.u0", "top"), "ram")
+        # not a slang instance name: unchanged
+        self.assertEqual(name("$paramod\\foo\\W=8", "top"), "$paramod\\foo\\W=8")
+        self.assertEqual(name("my$ram", "top"), "my$ram")
+        self.assertEqual(name("ram$top.u0", None), "ram$top.u0")
+
+    def test_copies_of_one_definition_must_agree(self):
+        yosys_json = {
+            "modules": {
+                "\\array_64x114$top.t0.u0": _firtool_rw_module(),
+                "\\array_64x114$top.t0.u1": _firtool_rw_module(64, 114, 1),
+            }
+        }
+        with self.assertRaises(ValueError):
+            detect.scan_yosys_json(yosys_json, top="top")
+
     def test_rw_port_pins_are_the_module_ports(self):
         (m,) = detect.scan_yosys_json(
             {"modules": {"\\array_64x114": _firtool_rw_module()}}
diff --git a/flow/scripts/memories/gen_memories.py b/flow/scripts/memories/gen_memories.py
index 9d179d7908..476a9d32fc 100644
--- a/flow/scripts/memories/gen_memories.py
+++ b/flow/scripts/memories/gen_memories.py
@@ -40,12 +40,13 @@ def run(
     platform: str,
     out_dir: Path,
     json_path: Path,
+    top: str | None = None,
 ) -> int:
     if platform != "asap7":
         sys.stderr.write(f"gen_memories: unsupported platform {platform}\n")
         return 1
 
-    found = detect.scan_yosys_json(yosys_json)
+    found = detect.scan_yosys_json(yosys_json, top)
 
     idiomatic.apply(found)
 
@@ -114,6 +115,11 @@ def main(argv: list[str] | None = None) -> int:
         type=Path,
         help="Path of the memories.json inventory to write.",
     )
+    p.add_argument(
+        "--top",
+        help="The design's top module, which slang's per-instance module "
+        "names carry.",
+    )
     args = p.parse_args(argv)
     return run(
         args.yosys_json,
@@ -121,6 +127,7 @@ def main(argv: list[str] | None = None) -> int:
         args.platform,
         args.out_dir,
         args.json,
+        args.top,
     )