diff --git a/app/src/legacyXr/assets/gamenative_openxr_runtime32.dll b/app/src/legacyXr/assets/gamenative_openxr_runtime32.dll
index 985e44faef..3d82a3bb96 100755
Binary files a/app/src/legacyXr/assets/gamenative_openxr_runtime32.dll and b/app/src/legacyXr/assets/gamenative_openxr_runtime32.dll differ
diff --git a/app/src/legacyXr/assets/gamenative_openxr_runtime64.dll b/app/src/legacyXr/assets/gamenative_openxr_runtime64.dll
index 6e0e3cfc26..52319ba377 100755
Binary files a/app/src/legacyXr/assets/gamenative_openxr_runtime64.dll and b/app/src/legacyXr/assets/gamenative_openxr_runtime64.dll differ
diff --git a/app/src/legacyXr/assets/payload.version b/app/src/legacyXr/assets/payload.version
index a3c2f6ec94..ec79990199 100644
--- a/app/src/legacyXr/assets/payload.version
+++ b/app/src/legacyXr/assets/payload.version
@@ -1 +1,7 @@
-3 fb4792ecc21725bec26e3e1754af6c954b39e0f641192d257e578629dea9c92c eb77fcd88b7a93c1fd28e8aaa05b22d0d454a11ebf488743cb4008a058d93e8e
\ No newline at end of file
+schema 4
+gamenative_openxr_runtime64.dll fb33c0718d08fa66219615c0b5e45e419d2b8edec002db664b4738de335bcd95
+gamenative_openxr_runtime32.dll 3df91ab0b2cc6fc6f5ef50ffe1d1f232df03ce71e3a8a4a78e891511a790c5db
+gamenative_xr_unixbridge.dll 669db5bc31a3437693925b07a897594b4f2b40a57c2ea169a5f9c4fbf0d78abe
+gamenative_xr_unixbridge32.dll 31bfc6815873e513991563bd781dc3a3272b8c13b78a66e9f9b8d7eb7509875e
+gamenative_xr_unixbridge.so e4e1cb74f4ee1a068e52fa81582e8cf206ea91fa574f51f545d3cc18a00ee9e0
+opencomposite_x64.dll 827ad85f3606a4dc4a8f5561a8ca69e4c6c1b5d2b9cd3315a461b9270b08242c
diff --git a/app/src/modernXr/assets/gamenative_openxr_runtime32.dll b/app/src/modernXr/assets/gamenative_openxr_runtime32.dll
index 985e44faef..3d82a3bb96 100755
Binary files a/app/src/modernXr/assets/gamenative_openxr_runtime32.dll and b/app/src/modernXr/assets/gamenative_openxr_runtime32.dll differ
diff --git a/app/src/modernXr/assets/gamenative_openxr_runtime64.dll b/app/src/modernXr/assets/gamenative_openxr_runtime64.dll
index 6e0e3cfc26..52319ba377 100755
Binary files a/app/src/modernXr/assets/gamenative_openxr_runtime64.dll and b/app/src/modernXr/assets/gamenative_openxr_runtime64.dll differ
diff --git a/app/src/modernXr/assets/payload.version b/app/src/modernXr/assets/payload.version
index a3c2f6ec94..ec79990199 100644
--- a/app/src/modernXr/assets/payload.version
+++ b/app/src/modernXr/assets/payload.version
@@ -1 +1,7 @@
-3 fb4792ecc21725bec26e3e1754af6c954b39e0f641192d257e578629dea9c92c eb77fcd88b7a93c1fd28e8aaa05b22d0d454a11ebf488743cb4008a058d93e8e
\ No newline at end of file
+schema 4
+gamenative_openxr_runtime64.dll fb33c0718d08fa66219615c0b5e45e419d2b8edec002db664b4738de335bcd95
+gamenative_openxr_runtime32.dll 3df91ab0b2cc6fc6f5ef50ffe1d1f232df03ce71e3a8a4a78e891511a790c5db
+gamenative_xr_unixbridge.dll 669db5bc31a3437693925b07a897594b4f2b40a57c2ea169a5f9c4fbf0d78abe
+gamenative_xr_unixbridge32.dll 31bfc6815873e513991563bd781dc3a3272b8c13b78a66e9f9b8d7eb7509875e
+gamenative_xr_unixbridge.so e4e1cb74f4ee1a068e52fa81582e8cf206ea91fa574f51f545d3cc18a00ee9e0
+opencomposite_x64.dll 827ad85f3606a4dc4a8f5561a8ca69e4c6c1b5d2b9cd3315a461b9270b08242c
diff --git a/tools/build-windows-xr-runtime.ps1 b/tools/build-windows-xr-runtime.ps1
index d51d8cebfd..d26cb26ff7 100644
--- a/tools/build-windows-xr-runtime.ps1
+++ b/tools/build-windows-xr-runtime.ps1
@@ -1,4 +1,5 @@
 param(
+    [ValidateSet("Release", "Debug")]
     [string]$Configuration = "Release"
 )
 
@@ -38,11 +39,14 @@ foreach ($architecture in @("x64", "x86")) {
     }
 }
 
+# Freestanding prevents builtin memory-loop recognition from making our CRT-less
+# memcpy/memset implementations call themselves. Keep normal floating-point semantics.
+$optimization = if ($Configuration -eq "Release") { "-O2" } else { "-O0" }
 $runtimeSource = Join-Path $source "gamenative_openxr_runtime.c"
 $runtime64 = Join-Path $build "gamenative_openxr_runtime64.dll"
 $runtime32 = Join-Path $build "gamenative_openxr_runtime32.dll"
-Invoke-Tool { & $clang --target=x86_64-w64-windows-gnu -shared -nostdlib "-Wl,-e,DllMain" -I $include -o $runtime64 $runtimeSource (Join-Path $source "gamenative_openxr_runtime_x64.def") $imports["ws2_32-x64"] $imports["kernel32-x64"] $imports["ntdll-x64"] $imports["dxgi-x64"] } "x64 OpenXR runtime"
-Invoke-Tool { & $clang --target=i686-w64-windows-gnu -shared -nostdlib "-Wl,-e,DllMain" -I $include -o $runtime32 $runtimeSource (Join-Path $source "gamenative_openxr_runtime_x86.def") $imports["ws2_32-x86"] $imports["kernel32-x86"] $imports["ntdll-x86"] $imports["dxgi-x86"] } "x86 OpenXR runtime"
+Invoke-Tool { & $clang --target=x86_64-w64-windows-gnu -shared -nostdlib -ffreestanding $optimization "-Wl,-e,DllMain" -I $include -o $runtime64 $runtimeSource (Join-Path $source "gamenative_openxr_runtime_x64.def") $imports["ws2_32-x64"] $imports["kernel32-x64"] $imports["ntdll-x64"] $imports["dxgi-x64"] } "x64 OpenXR runtime"
+Invoke-Tool { & $clang --target=i686-w64-windows-gnu -shared -nostdlib -ffreestanding $optimization "-Wl,-e,DllMain" -I $include -o $runtime32 $runtimeSource (Join-Path $source "gamenative_openxr_runtime_x86.def") $imports["ws2_32-x86"] $imports["kernel32-x86"] $imports["ntdll-x86"] $imports["dxgi-x86"] } "x86 OpenXR runtime"
 
 function Assert-Machine {
     param([string]$Path, [int]$Expected)
@@ -53,8 +57,11 @@ function Assert-Machine {
 }
 Assert-Machine $runtime64 0x8664
 Assert-Machine $runtime32 0x014c
-Copy-Item -Force -LiteralPath $runtime64 -Destination (Join-Path $output "gamenative_openxr_runtime64.dll")
-Copy-Item -Force -LiteralPath $runtime32 -Destination (Join-Path $output "gamenative_openxr_runtime32.dll")
-$hash64 = (Get-FileHash -Algorithm SHA256 -LiteralPath $runtime64).Hash.ToLowerInvariant()
-$hash32 = (Get-FileHash -Algorithm SHA256 -LiteralPath $runtime32).Hash.ToLowerInvariant()
-Set-Content -NoNewline -LiteralPath (Join-Path $output "payload.version") -Value "3 $hash64 $hash32"
+foreach ($flavor in @("modernXr", "legacyXr")) {
+    $assets = Join-Path $repository "app\src\$flavor\assets"
+    New-Item -ItemType Directory -Force -Path $assets | Out-Null
+    Copy-Item -Force -LiteralPath $runtime64 -Destination (Join-Path $assets "gamenative_openxr_runtime64.dll")
+    Copy-Item -Force -LiteralPath $runtime32 -Destination (Join-Path $assets "gamenative_openxr_runtime32.dll")
+}
+& (Join-Path $PSScriptRoot "verify-xr-payload.ps1")
+Copy-Item -Force -LiteralPath (Join-Path $output "payload.version") -Destination (Join-Path $repository "app\src\legacyXr\assets\payload.version")
diff --git a/tools/build-xr-payload-macos.sh b/tools/build-xr-payload-macos.sh
index 2866ea4e48..8076198053 100755
--- a/tools/build-xr-payload-macos.sh
+++ b/tools/build-xr-payload-macos.sh
@@ -37,12 +37,12 @@ for lib in ws2_32 kernel32 ntdll dxgi; do
     "$bin/llvm-dlltool" -m i386 -k -d "$source_dir/${lib}_x86.def" -l "$work/lib${lib}_x86.a"
 done
 
-# The two OpenXR runtime DLLs (CRT-less PE, built with the NDK's clang).
-"$bin/clang" --target=x86_64-w64-windows-gnu -shared -nostdlib -Wl,-e,DllMain -I "$work/inc" \
+# Release optimization; freestanding keeps our CRT-less memory helpers from recursing.
+"$bin/clang" --target=x86_64-w64-windows-gnu -shared -nostdlib -ffreestanding -O2 -Wl,-e,DllMain -I "$work/inc" \
     -o "$output/gamenative_openxr_runtime64.dll" \
     "$source_dir/gamenative_openxr_runtime.c" "$source_dir/gamenative_openxr_runtime_x64.def" \
     "$work/libws2_32_x64.a" "$work/libkernel32_x64.a" "$work/libntdll_x64.a" "$work/libdxgi_x64.a"
-"$bin/clang" --target=i686-w64-windows-gnu -shared -nostdlib -Wl,-e,DllMain -I "$work/inc" \
+"$bin/clang" --target=i686-w64-windows-gnu -shared -nostdlib -ffreestanding -O2 -Wl,-e,DllMain -I "$work/inc" \
     -o "$output/gamenative_openxr_runtime32.dll" \
     "$source_dir/gamenative_openxr_runtime.c" "$source_dir/gamenative_openxr_runtime_x86.def" \
     "$work/libws2_32_x86.a" "$work/libkernel32_x86.a" "$work/libntdll_x86.a" "$work/libdxgi_x86.a"