diff --git a/runtime/CMakeLists.txt b/runtime/CMakeLists.txt
index 46c476a3..9b74e42c 100644
--- a/runtime/CMakeLists.txt
+++ b/runtime/CMakeLists.txt
@@ -393,6 +393,15 @@ if(BUILD_TESTING)
         include
         ../recompiler/lib/toml11)
     target_link_libraries(mod_runtime_test PRIVATE chdr-static)
+    # The real disc hasher uses a 1 MiB scratch buffer. Match the runtime's
+    # stack allowance instead of overflowing MinGW's 1 MiB executable default.
+    if(WIN32)
+        if(MSVC)
+            target_link_options(mod_runtime_test PRIVATE /STACK:16777216)
+        else()
+            target_link_options(mod_runtime_test PRIVATE -Wl,--stack,16777216)
+        endif()
+    endif()
     add_test(NAME mod_runtime_test COMMAND mod_runtime_test)
 
     if(WIN32)
diff --git a/runtime/tests/test_dirty_text_continuation_guards.py b/runtime/tests/test_dirty_text_continuation_guards.py
index 56aa21ea..751fef44 100644
--- a/runtime/tests/test_dirty_text_continuation_guards.py
+++ b/runtime/tests/test_dirty_text_continuation_guards.py
@@ -18,13 +18,15 @@ def main() -> int:
 
     required_range_fragments = (
         "uint32_t exec_pc",
-        "if (phys + len <= at) continue;",
-        "len -= at - phys;",
+        "(void)exec_pc;",
+        "memcmp(ram + phys, text_ref_image + (phys - text_ref_lo), len)",
         "if (!any)",
     )
     for fragment in required_range_fragments:
         if fragment not in range_guard:
             raise AssertionError(f"missing continuation range guard: {fragment}")
+    if "len -= at - phys;" in range_guard or "if (phys + len <= at) continue;" in range_guard:
+        raise AssertionError("continuation guard clips away code reachable by a backward edge")
     if "text_diverged_bitmap" in range_guard:
         raise AssertionError("exact-range mismatch still sticky-poisons a whole page")
     if "dirty_ram_text_native_ok_ranges_from(lo_len_pairs, count, 0u)" not in memory:
diff --git a/runtime/tests/test_launcher_vulkan_option.py b/runtime/tests/test_launcher_vulkan_option.py
index ad460ece..06d51d37 100644
--- a/runtime/tests/test_launcher_vulkan_option.py
+++ b/runtime/tests/test_launcher_vulkan_option.py
@@ -2,10 +2,10 @@
 from pathlib import Path
 
 root = Path(__file__).resolve().parents[2]
-main = (root / "runtime" / "src" / "main.cpp").read_text()
-config_h = (root / "recompiler" / "src" / "config_loader.h").read_text()
-config_cpp = (root / "recompiler" / "src" / "config_loader.cpp").read_text()
-runtime_cmake = (root / "runtime" / "runtime.cmake").read_text()
+main = (root / "runtime" / "src" / "main.cpp").read_text(encoding="utf-8")
+config_h = (root / "recompiler" / "src" / "config_loader.h").read_text(encoding="utf-8")
+config_cpp = (root / "recompiler" / "src" / "config_loader.cpp").read_text(encoding="utf-8")
+runtime_cmake = (root / "runtime" / "runtime.cmake").read_text(encoding="utf-8")
 
 assert "runtime/" + "launcher" not in runtime_cmake
 assert "Rml" + "Ui" not in runtime_cmake
diff --git a/runtime/tests/test_overlay_pair_dedup_runtime.py b/runtime/tests/test_overlay_pair_dedup_runtime.py
index 957dfba8..187d8612 100644
--- a/runtime/tests/test_overlay_pair_dedup_runtime.py
+++ b/runtime/tests/test_overlay_pair_dedup_runtime.py
@@ -7,10 +7,11 @@ import argparse
 import os
 import pathlib
 import platform
-import re
 import shutil
 import subprocess
+import sys
 import tempfile
+from unittest.mock import patch
 import zlib
 
 
@@ -23,21 +24,12 @@ RESIDENT = "psxrecomp bios resident shard v1\n"
 
 
 def codegen_leaf() -> str:
-    api = (RUNTIME / "include" / "overlay_api.h")
-    hash_header = (RUNTIME / "include" / "overlay_codegen_hash.h")
-    version = "0"
-    code_hash = "00000000"
-    if api.is_file():
-        match = re.search(r"PSX_OVERLAY_CODEGEN_VER\s+(\d+)",
-                          api.read_text(encoding="utf-8"))
-        if match:
-            version = match.group(1)
-    if hash_header.is_file():
-        match = re.search(r"PSX_OVERLAY_CODEGEN_HASH\s+0x([0-9A-Fa-f]{8})",
-                          hash_header.read_text(encoding="utf-8"))
-        if match:
-            code_hash = match.group(1).lower()
-    return f"cg{version}_{code_hash}_gc00000000_f0"
+    sys.path.insert(0, str(ROOT / "tools"))
+    import compile_overlays
+    # The synthetic loader uses a zero config hash; serialize its namespace
+    # with the production owner so new namespace fields cannot go stale here.
+    with patch.object(compile_overlays, "overlay_config_hash", return_value=0):
+        return compile_overlays.cache_tag(str(RUNTIME / "include"), "", "")
 
 
 def arch_abi() -> str:
diff --git a/runtime/tests/test_release_zip.py b/runtime/tests/test_release_zip.py
index 2431963a..73131af2 100644
--- a/runtime/tests/test_release_zip.py
+++ b/runtime/tests/test_release_zip.py
@@ -16,8 +16,8 @@ with tempfile.TemporaryDirectory() as temporary:
     stage = base / "stage"
     (stage / "mods" / "package").mkdir(parents=True)
     (stage / "Tomba Recompiled.exe").write_bytes(b"exe")
-    (stage / "mods" / "package" / "manifest.toml").write_text(
-        'id = "test"\n', encoding="utf-8"
+    (stage / "mods" / "package" / "manifest.toml").write_bytes(
+        b'id = "test"\n'
     )
     output = base / "release.zip"
     subprocess.run(