diff --git a/.efrocachemap b/.efrocachemap
index 8b203d9e..e6aca954 100644
--- a/.efrocachemap
+++ b/.efrocachemap
@@ -4069,18 +4069,18 @@
   "build/prefab/full/linux_x86_64_gui/release/ballisticakit": "e5db667cca97477bdc53745597ce96c0",
   "build/prefab/full/linux_x86_64_server/debug/dist/ballisticakit_headless": "a691fe1725d4e3e8659d4a8910767a6b",
   "build/prefab/full/linux_x86_64_server/release/dist/ballisticakit_headless": "757d3686278016f0a8c14ca32351869f",
-  "build/prefab/full/mac_arm64_gui/debug/ballisticakit": "7882e6a67274134121269297adba650c",
+  "build/prefab/full/mac_arm64_gui/debug/ballisticakit": "1f4113367d9314392e9f735d169880b6",
   "build/prefab/full/mac_arm64_gui/release/ballisticakit": "e0aad2e5e0429f267c68e1adc01f4de2",
-  "build/prefab/full/mac_arm64_server/debug/dist/ballisticakit_headless": "2949c67081ab95fa6b3c200b6e8dac90",
+  "build/prefab/full/mac_arm64_server/debug/dist/ballisticakit_headless": "eb5e74ea7434d314c8e3775db5fbb46e",
   "build/prefab/full/mac_arm64_server/release/dist/ballisticakit_headless": "7f3147c3eb2d6b47d060cec361333609",
-  "build/prefab/full/mac_x86_64_gui/debug/ballisticakit": "8e651eb94e21d37c38831363d2bf06d3",
+  "build/prefab/full/mac_x86_64_gui/debug/ballisticakit": "558d5de83a26abe0da6c56d20918d0e6",
   "build/prefab/full/mac_x86_64_gui/release/ballisticakit": "60e4941df0d4d6f05f4f5d4497f5b31f",
-  "build/prefab/full/mac_x86_64_server/debug/dist/ballisticakit_headless": "906d81ef963eb5817f9a09dacdb42496",
+  "build/prefab/full/mac_x86_64_server/debug/dist/ballisticakit_headless": "ba913b1cbf2fab9da6f00bef768e99f5",
   "build/prefab/full/mac_x86_64_server/release/dist/ballisticakit_headless": "c4908dc4c7bff0f87e2469b145e9fe64",
-  "build/prefab/full/windows_x86_gui/debug/BallisticaKit.exe": "af603ec4c7548c309c560aa78d80209c",
-  "build/prefab/full/windows_x86_gui/release/BallisticaKit.exe": "e084002e7c8dcced5e671535d819423b",
-  "build/prefab/full/windows_x86_server/debug/dist/BallisticaKitHeadless.exe": "d20a89662c0d976cb5c3559b553913b7",
-  "build/prefab/full/windows_x86_server/release/dist/BallisticaKitHeadless.exe": "1fe7fa727099fcf24eaf260d74cb3ae4",
+  "build/prefab/full/windows_x86_gui/debug/BallisticaKit.exe": "65f8b9df27e56bb9d44289475e8752c6",
+  "build/prefab/full/windows_x86_gui/release/BallisticaKit.exe": "ddc6bbf0e792502c05bbfc7d22f5f36c",
+  "build/prefab/full/windows_x86_server/debug/dist/BallisticaKitHeadless.exe": "4966a48d90426c00d566cb73c7a5bb4e",
+  "build/prefab/full/windows_x86_server/release/dist/BallisticaKitHeadless.exe": "421eccd01f494e8b16108c115f9c454e",
   "build/prefab/lib/linux_arm64_gui/debug/libballisticaplus.a": "d9865523059d8cf11b2bef4b9da9a8c9",
   "build/prefab/lib/linux_arm64_gui/release/libballisticaplus.a": "56d6440f62c271c4ce9ef520400395a3",
   "build/prefab/lib/linux_arm64_server/debug/libballisticaplus.a": "d9865523059d8cf11b2bef4b9da9a8c9",
@@ -4097,14 +4097,14 @@
   "build/prefab/lib/mac_x86_64_gui/release/libballisticaplus.a": "c2cf0dc227e41a826c913d12e117c316",
   "build/prefab/lib/mac_x86_64_server/debug/libballisticaplus.a": "fbdc80e41c5883b4a893d2f0786e377f",
   "build/prefab/lib/mac_x86_64_server/release/libballisticaplus.a": "c2cf0dc227e41a826c913d12e117c316",
-  "build/prefab/lib/windows/Debug_Win32/BallisticaKitGenericPlus.lib": "80963fe5c501c728c16bb9fccb2b59ab",
-  "build/prefab/lib/windows/Debug_Win32/BallisticaKitGenericPlus.pdb": "ba75fa26bde66b7ee80cf8f840ff1806",
-  "build/prefab/lib/windows/Debug_Win32/BallisticaKitHeadlessPlus.lib": "847bf3a0acffb54856509c53e18c1656",
-  "build/prefab/lib/windows/Debug_Win32/BallisticaKitHeadlessPlus.pdb": "480b7d544c3c0b642bcf5aae73641cfe",
-  "build/prefab/lib/windows/Release_Win32/BallisticaKitGenericPlus.lib": "f1ecc6a4e2e034fb5c6b483b798cc68d",
-  "build/prefab/lib/windows/Release_Win32/BallisticaKitGenericPlus.pdb": "3cfcded3e0b07261ffb5b6828993c89b",
-  "build/prefab/lib/windows/Release_Win32/BallisticaKitHeadlessPlus.lib": "9cc7af3fc84382412f03b4482e4c847e",
-  "build/prefab/lib/windows/Release_Win32/BallisticaKitHeadlessPlus.pdb": "e64ca3bc0adc45804fb6a558dc925a36",
+  "build/prefab/lib/windows/Debug_Win32/BallisticaKitGenericPlus.lib": "519286657455b41232a1faa946d41c2c",
+  "build/prefab/lib/windows/Debug_Win32/BallisticaKitGenericPlus.pdb": "56629dc18b297fc90ddd4a2e64906943",
+  "build/prefab/lib/windows/Debug_Win32/BallisticaKitHeadlessPlus.lib": "71735c7abee709e3f0b3de828a342726",
+  "build/prefab/lib/windows/Debug_Win32/BallisticaKitHeadlessPlus.pdb": "1dc5bb0bcab746e2ed3d4ee95e96b228",
+  "build/prefab/lib/windows/Release_Win32/BallisticaKitGenericPlus.lib": "b149369e859494ff0bf4ee3e3148969a",
+  "build/prefab/lib/windows/Release_Win32/BallisticaKitGenericPlus.pdb": "2406289654622f7faf67c797ca16069c",
+  "build/prefab/lib/windows/Release_Win32/BallisticaKitHeadlessPlus.lib": "46cac43de3e45317c5b8296eaad873ce",
+  "build/prefab/lib/windows/Release_Win32/BallisticaKitHeadlessPlus.pdb": "82405a82c0780693e65ead6b85263780",
   "src/assets/ba_data/python/babase/_mgen/__init__.py": "f885fed7f2ed98ff2ba271f9dbe3391c",
   "src/assets/ba_data/python/babase/_mgen/enums.py": "b611c090513a21e2fe90e56582724e9d",
   "src/ballistica/base/mgen/pyembed/binding_base.inc": "72bfed2cce8ff19741989dec28302f3f",
diff --git a/tools/batools/apprun.py b/tools/batools/apprun.py
index 14771bfe..0e8afd9c 100755
--- a/tools/batools/apprun.py
+++ b/tools/batools/apprun.py
@@ -105,6 +105,9 @@ def acquire_binary(assets: bool, purpose: str) -> str:
     if os.environ.get('BA_APP_RUN_ENABLE_BUILDS') == '1':
         # Going the build-it-ourselves route.
 
+        # Don't need any env mods for this path.
+        env = None
+
         if os.environ.get('BA_APP_RUN_BUILD_HEADLESS') == '1':
             # User has opted for headless builds.
             if assets:
@@ -143,6 +146,11 @@ def acquire_binary(assets: bool, purpose: str) -> str:
     else:
         # Ok; going with a downloaded prefab headless build.
 
+        # By default, prefab build targets on WSL (Linux running on
+        # Windows) will give us Windows builds which won't work right
+        # here. Ask it for Linux builds instead.
+        env = dict(os.environ, BA_WSL_TARGETS_WINDOWS='0')
+
         # Let the user know how to use their own built binaries instead
         # if they prefer.
         note = '\n' + textwrap.fill(
@@ -152,6 +160,7 @@ def acquire_binary(assets: bool, purpose: str) -> str:
             f' you\'ve made to the C/C++ layer.',
             80,
         )
+
         if assets:
             print(
                 f'{Clr.SMAG}Fetching prefab binary & assets for'
@@ -161,6 +170,7 @@ def acquire_binary(assets: bool, purpose: str) -> str:
             binary_path = (
                 subprocess.run(
                     ['tools/pcommand', 'prefab_binary_path', 'server-release'],
+                    env=env,
                     check=True,
                     capture_output=True,
                 )
@@ -177,6 +187,7 @@ def acquire_binary(assets: bool, purpose: str) -> str:
             binary_path = (
                 subprocess.run(
                     ['tools/pcommand', 'prefab_binary_path', 'server-release'],
+                    env=env,
                     check=True,
                     capture_output=True,
                 )
@@ -185,7 +196,7 @@ def acquire_binary(assets: bool, purpose: str) -> str:
             )
             binary_build_command = ['make', binary_path]
 
-    subprocess.run(binary_build_command, check=True)
+    subprocess.run(binary_build_command, env=env, check=True)
     if not os.path.exists(binary_path):
         raise RuntimeError(
             f"Binary not found at expected path '{binary_path}'."