diff --git a/.efrocachemap b/.efrocachemap
index 1284b1c2..bd605e06 100644
--- a/.efrocachemap
+++ b/.efrocachemap
@@ -4080,18 +4080,18 @@
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   "build/prefab/full/linux_x86_64_server/debug/dist/ballisticakit_headless": "https://files.ballistica.net/cache/ba1/9f/37/b4553f9f9fda9fb07d7f3f3ab2f6",
   "build/prefab/full/linux_x86_64_server/release/dist/ballisticakit_headless": "https://files.ballistica.net/cache/ba1/cf/b4/d955fed8589fd59e0f15e69ab568",
-  "build/prefab/full/mac_arm64_gui/debug/ballisticakit": "https://files.ballistica.net/cache/ba1/dc/44/de081983fef203f8ffcd0b553e19",
+  "build/prefab/full/mac_arm64_gui/debug/ballisticakit": "https://files.ballistica.net/cache/ba1/12/83/23a307429d4a729f562b954400f6",
   "build/prefab/full/mac_arm64_gui/release/ballisticakit": "https://files.ballistica.net/cache/ba1/b1/2f/33ad58bdcbcb2ac5de570b7b86d4",
-  "build/prefab/full/mac_arm64_server/debug/dist/ballisticakit_headless": "https://files.ballistica.net/cache/ba1/d6/c7/623425ad23b0e49a0cd6ce28fddb",
+  "build/prefab/full/mac_arm64_server/debug/dist/ballisticakit_headless": "https://files.ballistica.net/cache/ba1/a5/56/1b4153622fd9c8d2a1e7f14cf3b7",
   "build/prefab/full/mac_arm64_server/release/dist/ballisticakit_headless": "https://files.ballistica.net/cache/ba1/d4/50/fc305556a2926c5c69004b49a09a",
-  "build/prefab/full/mac_x86_64_gui/debug/ballisticakit": "https://files.ballistica.net/cache/ba1/be/be/51940a5b107d09f206fb3989c395",
+  "build/prefab/full/mac_x86_64_gui/debug/ballisticakit": "https://files.ballistica.net/cache/ba1/a6/95/4745877e61819b8d9747960ca8d4",
   "build/prefab/full/mac_x86_64_gui/release/ballisticakit": "https://files.ballistica.net/cache/ba1/bc/5d/513cbfa9287f138912cb73f61783",
-  "build/prefab/full/mac_x86_64_server/debug/dist/ballisticakit_headless": "https://files.ballistica.net/cache/ba1/12/57/859c0ebc30c2467eaecbd768c66a",
+  "build/prefab/full/mac_x86_64_server/debug/dist/ballisticakit_headless": "https://files.ballistica.net/cache/ba1/79/2d/0606820548fc2d0f84ceff572049",
   "build/prefab/full/mac_x86_64_server/release/dist/ballisticakit_headless": "https://files.ballistica.net/cache/ba1/e3/71/cd19381bd0a9c81f112dd90868ae",
-  "build/prefab/full/windows_x86_gui/debug/BallisticaKit.exe": "https://files.ballistica.net/cache/ba1/47/22/419a37ddd3b768ca0dd51705bbde",
-  "build/prefab/full/windows_x86_gui/release/BallisticaKit.exe": "https://files.ballistica.net/cache/ba1/eb/13/cc6b88e80228c3fc223445e21e89",
-  "build/prefab/full/windows_x86_server/debug/dist/BallisticaKitHeadless.exe": "https://files.ballistica.net/cache/ba1/a4/f2/5d5be9f42dd24ae9b892601ad683",
-  "build/prefab/full/windows_x86_server/release/dist/BallisticaKitHeadless.exe": "https://files.ballistica.net/cache/ba1/5e/24/95785e5bedfd942bf210b3865148",
+  "build/prefab/full/windows_x86_gui/debug/BallisticaKit.exe": "https://files.ballistica.net/cache/ba1/a4/a8/577d056e8566cd1c084db7f8aaab",
+  "build/prefab/full/windows_x86_gui/release/BallisticaKit.exe": "https://files.ballistica.net/cache/ba1/c3/33/1967e1c77d409733e636b5883a85",
+  "build/prefab/full/windows_x86_server/debug/dist/BallisticaKitHeadless.exe": "https://files.ballistica.net/cache/ba1/e4/ed/88f5da9640034d053fd68e34b356",
+  "build/prefab/full/windows_x86_server/release/dist/BallisticaKitHeadless.exe": "https://files.ballistica.net/cache/ba1/37/c6/42b4eb716aed07f9a9ed5e1b5bc1",
   "build/prefab/lib/linux_arm64_gui/debug/libballistica_plus.a": "https://files.ballistica.net/cache/ba1/98/32/43c61f1e11520f764158cf0e76d2",
   "build/prefab/lib/linux_arm64_gui/release/libballistica_plus.a": "https://files.ballistica.net/cache/ba1/ca/65/cba463f21a8f76c5bbfe27cae124",
   "build/prefab/lib/linux_arm64_server/debug/libballistica_plus.a": "https://files.ballistica.net/cache/ba1/73/20/119211f1700bb5a410cedf4e76f2",
@@ -4108,14 +4108,14 @@
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   "build/prefab/lib/mac_x86_64_server/debug/libballistica_plus.a": "https://files.ballistica.net/cache/ba1/2e/c7/873af48627997b6fab4b2c4ba6bc",
   "build/prefab/lib/mac_x86_64_server/release/libballistica_plus.a": "https://files.ballistica.net/cache/ba1/3a/94/4780fada10f0fc3f43a54f29c86f",
-  "build/prefab/lib/windows/Debug_Win32/BallisticaKitGenericPlus.lib": "https://files.ballistica.net/cache/ba1/71/8c/540e4c3efe754041b26a2947b14a",
-  "build/prefab/lib/windows/Debug_Win32/BallisticaKitGenericPlus.pdb": "https://files.ballistica.net/cache/ba1/f1/86/454aac22681002628615187d28f6",
-  "build/prefab/lib/windows/Debug_Win32/BallisticaKitHeadlessPlus.lib": "https://files.ballistica.net/cache/ba1/fa/da/f218c6e71f7c56c47ddf7ba91ef8",
-  "build/prefab/lib/windows/Debug_Win32/BallisticaKitHeadlessPlus.pdb": "https://files.ballistica.net/cache/ba1/6c/26/3ca064faa1000fb69e41eba24425",
-  "build/prefab/lib/windows/Release_Win32/BallisticaKitGenericPlus.lib": "https://files.ballistica.net/cache/ba1/75/7a/4122bb4143cb68872b5b3dcebe49",
-  "build/prefab/lib/windows/Release_Win32/BallisticaKitGenericPlus.pdb": "https://files.ballistica.net/cache/ba1/97/20/6ec2421f83b1e9a1ca937e36a588",
-  "build/prefab/lib/windows/Release_Win32/BallisticaKitHeadlessPlus.lib": "https://files.ballistica.net/cache/ba1/ad/e9/b86c0a5a916f4ec3c2e586f0604f",
-  "build/prefab/lib/windows/Release_Win32/BallisticaKitHeadlessPlus.pdb": "https://files.ballistica.net/cache/ba1/d1/a8/c5ccf4c0bb5b504c5e32adaa98a3",
+  "build/prefab/lib/windows/Debug_Win32/BallisticaKitGenericPlus.lib": "https://files.ballistica.net/cache/ba1/b7/3d/d6ab07ea8b3b58c6605ae7864eec",
+  "build/prefab/lib/windows/Debug_Win32/BallisticaKitGenericPlus.pdb": "https://files.ballistica.net/cache/ba1/ad/86/03386a6e15c55e0661e932044c60",
+  "build/prefab/lib/windows/Debug_Win32/BallisticaKitHeadlessPlus.lib": "https://files.ballistica.net/cache/ba1/d3/87/d8024acf61db6b471bc5aa19e57f",
+  "build/prefab/lib/windows/Debug_Win32/BallisticaKitHeadlessPlus.pdb": "https://files.ballistica.net/cache/ba1/f5/1b/783a8c5673613b66fc73b16724ee",
+  "build/prefab/lib/windows/Release_Win32/BallisticaKitGenericPlus.lib": "https://files.ballistica.net/cache/ba1/54/92/f516fb3937a7c0c52bffdcb223f2",
+  "build/prefab/lib/windows/Release_Win32/BallisticaKitGenericPlus.pdb": "https://files.ballistica.net/cache/ba1/2b/8c/59209d69c14c866957e83d6a5495",
+  "build/prefab/lib/windows/Release_Win32/BallisticaKitHeadlessPlus.lib": "https://files.ballistica.net/cache/ba1/1f/a5/5b2f8514ce9eccadea84c0d1c7e9",
+  "build/prefab/lib/windows/Release_Win32/BallisticaKitHeadlessPlus.pdb": "https://files.ballistica.net/cache/ba1/d8/d2/727ea6711db0cbc9e03b7a995b46",
   "src/assets/ba_data/python/babase/_mgen/__init__.py": "https://files.ballistica.net/cache/ba1/52/c6/c11130af7b10d6c0321add5518fa",
   "src/assets/ba_data/python/babase/_mgen/enums.py": "https://files.ballistica.net/cache/ba1/38/c3/1dedd5e74f2508efc5974c8815a1",
   "src/ballistica/base/mgen/pyembed/binding_base.inc": "https://files.ballistica.net/cache/ba1/4e/07/87dd93e7ef29b8b78d0b4791d6f8",
diff --git a/tools/batools/build.py b/tools/batools/build.py
index fd61be6f..f5c17a9f 100644
--- a/tools/batools/build.py
+++ b/tools/batools/build.py
@@ -210,6 +210,15 @@ def lazybuild(target: str, category: LazyBuildCategory, command: str) -> None:
 
     # Everything possibly affecting asset builds.
     elif category is LazyBuildCategory.ASSETS:
+
+        def _filefilter(root: str, filename: str) -> bool:
+            # Exclude tools/spinoff; it doesn't affect asset builds
+            # and we don't want to break if it is a symlink pointing
+            # to a not-present parent repo.
+            if root == 'tools' and filename == 'spinoff':
+                return False
+            return True
+
         LazyBuildContext(
             target=target,
             # Even though this category currently doesn't run any
@@ -222,6 +231,7 @@ def lazybuild(target: str, category: LazyBuildCategory, command: str) -> None:
                 'src/assets',
             ],
             command=command,
+            filefilter=_filefilter,
         ).run()
 
     else: