diff --git a/docs/internal/upstream/duckstation-texture-format-and-xxhash.md b/docs/internal/upstream/duckstation-texture-format-and-xxhash.md
new file mode 100644
index 00000000..e252cae2
--- /dev/null
+++ b/docs/internal/upstream/duckstation-texture-format-and-xxhash.md
@@ -0,0 +1,40 @@
+# DuckStation texture format and xxHash provenance
+
+The independent format integration is described in
+[DuckStation texture format notes](../../DUCKSTATION_TEXTURE_FORMAT.md).
+Reference behavior was observed at DuckStation commit
+[697599c47a646a6cfcc4d246018adf4904d55001](https://github.com/stenzek/duckstation/tree/697599c47a646a6cfcc4d246018adf4904d55001),
+whose [license](https://github.com/stenzek/duckstation/blob/697599c47a646a6cfcc4d246018adf4904d55001/LICENSE)
+is CC-BY-NC-ND-4.0. DuckStation is authored by Stenzek and its contributors;
+its authorship is credited by the pinned reference links. No DuckStation
+implementation, translated implementation, patch, or binary is included,
+and no DuckStation co-author trailer is claimed for this independent work.
+
+Implemented behavior: bounded modern texture filenames and palette ranges,
+XXH3 identities over native pixel sources and palettes, supported alpha
+classification, replacement loading, and original-texture dumping. Related
+coalescing, copy/split identities, multi-image composition, wrapped footprints,
+JPEG/WebP decoding, and DuckStation rendering/cache implementation are excluded.
+The format guide records the exact compatibility limits.
+
+The only vendored implementation is unmodified
+[xxHash v0.8.3](https://github.com/Cyan4973/xxHash/tree/v0.8.3), authored by Yann
+Collet and contributors under
+[BSD-2-Clause](https://github.com/Cyan4973/xxHash/blob/v0.8.3/LICENSE).
+`runtime/third_party/xxhash.h` retains its original copyright and license;
+its SHA-256 is
+`17973c0dc49d9854ca26caa191f0e12f7a424b68858d9a78de3860d959d85e4b`.
+Player packages carry `runtime/licenses/xxhash-NOTICES.txt` as a runtime
+notice. Vendoring preserves authorship in the unmodified source and notices,
+rather than attributing that source to this change's author.
+
+Validation on current framework master `92c0f3cd`: registered DuckStation
+module and OpenGL renderer tests pass, alongside mod package, builtin
+manifest, runtime, and resident tests. Independent xxHash wheel vectors,
+literal filenames, PNG pixels and file preservation, cache/reload behavior,
+alpha handling, upload aborts, and native VRAM invariance are covered.
+Tomba USA title and Village gameplay showed synthetic replacements, with
+live off/reload/on and stable native texture atlas comparisons. Full scene
+coverage and third-party artwork packs were not claimed; the first consumer
+needs a framework pin update and runtime rebuild, without a game C regen
+for the HD texture feature itself.
diff --git a/runtime/tests/test_gpu_upload_history.py b/runtime/tests/test_gpu_upload_history.py
index edc0cf8d..4e66f949 100644
--- a/runtime/tests/test_gpu_upload_history.py
+++ b/runtime/tests/test_gpu_upload_history.py
@@ -29,6 +29,7 @@ static int gp0_state;
 enum {GP0_VRAM_WRITE=2};
 static struct {uint32_t gpr[32];} *debug_cpu_ptr;
 uint32_t psx_read_word(uint32_t addr){(void)addr;assert(0);return 0;}
+void gr_vram_upload_begin(int x,int y,int w,int h){(void)x;(void)y;(void)w;(void)h;}
 """+production+'\nstatic void capture(uint32_t val) {\n'+capture+'}\n'+r"""
 int main(void) {
  gp0_cmd_buf[1]=7|(9u<<16);gp0_cmd_buf[2]=4|(1u<<16);