diff --git a/rtl/mini/formal/generate_formal_filelist.py b/rtl/mini/formal/generate_formal_filelist.py
index 48f1ae6e..dba496e7 100644
--- a/rtl/mini/formal/generate_formal_filelist.py
+++ b/rtl/mini/formal/generate_formal_filelist.py
@@ -26,7 +26,9 @@ TOP = ROOT / "rtl/mini/top"
 
 
 def target_defines(target: str) -> list[str]:
-    if target in {"onchip_ram", "opipsram"}:
+    if target == "onchip_ram":
+        return ["+define+PDK_BEHAV", "+define+SYNTHESIS"]
+    if target == "opipsram":
         return ["+define+PDK_BEHAV"]
     if target == "sysctrl":
         return ["+define+SV_ASSRT_DISABLE", "+define+MINI_PRODUCT"]
diff --git a/tests/test_script_tools.py b/tests/test_script_tools.py
index 2fddb6a1..9b56c522 100644
--- a/tests/test_script_tools.py
+++ b/tests/test_script_tools.py
@@ -327,6 +327,7 @@ def test_formal_filelists_are_scoped_to_the_protocol_duts(tmp_path: Path) -> Non
     ws2812_filelist = tmp_path / "ws2812.fl"
     i2c_filelist = tmp_path / "i2c.fl"
     clint_filelist = tmp_path / "clint.fl"
+    onchip_ram_filelist = tmp_path / "onchip_ram.fl"
     opipsram_filelist = tmp_path / "opipsram.fl"
     assert generate_formal_filelist("bus", bus_filelist, memory_map, topology, user_extensions)
     assert generate_formal_filelist(
@@ -347,6 +348,9 @@ def test_formal_filelists_are_scoped_to_the_protocol_duts(tmp_path: Path) -> Non
     )
     assert generate_formal_filelist("i2c", i2c_filelist, memory_map, topology, user_extensions)
     assert generate_formal_filelist("clint", clint_filelist, memory_map, topology, user_extensions)
+    assert generate_formal_filelist(
+        "onchip_ram", onchip_ram_filelist, memory_map, topology, user_extensions
+    )
     assert generate_formal_filelist(
         "opipsram", opipsram_filelist, memory_map, topology, user_extensions
     )
@@ -360,9 +364,13 @@ def test_formal_filelists_are_scoped_to_the_protocol_duts(tmp_path: Path) -> Non
     ws2812 = parse_filelists([ws2812_filelist], require_files=False)
     i2c = parse_filelists([i2c_filelist], require_files=False)
     clint = parse_filelists([clint_filelist], require_files=False)
+    onchip_ram = parse_filelists([onchip_ram_filelist], require_files=False)
     opipsram = parse_filelists([opipsram_filelist], require_files=False)
     assert "+define+SV_ASSRT_DISABLE" in bus.defines
+    assert "+define+PDK_BEHAV" in onchip_ram.defines
+    assert "+define+SYNTHESIS" in onchip_ram.defines
     assert "+define+PDK_BEHAV" in opipsram.defines
+    assert "+define+SYNTHESIS" not in opipsram.defines
     assert "+define+SV_ASSRT_DISABLE" not in opipsram.defines
     assert ROOT / "rtl/mini/top/rib_bus.sv" in bus.files
     assert ROOT / "rtl/mini/top/rib_if.sv" in bus.files