diff --git a/core/libs/prx/libSceGameUpdate/Export.cpp b/core/libs/prx/libSceGameUpdate/Export.cpp
index 0e3ef3835e..7c61d2507d 100644
--- a/core/libs/prx/libSceGameUpdate/Export.cpp
+++ b/core/libs/prx/libSceGameUpdate/Export.cpp
@@ -176,4 +176,8 @@ int APS5_VABI sceGameUpdateTerminate(void) {
     return 0;
 }
 
+int APS5_VABI sceGameUpdateCheckTitle() {
+    NotImplemented_nid_no_patch(__func__);
+}
+
 }
diff --git a/core/libs/prx/libSceGameUpdate/include/Api.hpp b/core/libs/prx/libSceGameUpdate/include/Api.hpp
index 2de12ef941..f7d282e665 100644
--- a/core/libs/prx/libSceGameUpdate/include/Api.hpp
+++ b/core/libs/prx/libSceGameUpdate/include/Api.hpp
@@ -11,5 +11,6 @@ int APS5_VABI sceGameUpdateDeleteRequest(int requestId);
 int APS5_VABI sceGameUpdateGetAddcontLatestVersion(uint32_t serviceLabel, const NpUnifiedEntitlementLabel* entitlementLabel, GameUpdateAddcontVersionInfo* info);
 int APS5_VABI sceGameUpdateInitialize(void);
 int APS5_VABI sceGameUpdateTerminate(void);
+int APS5_VABI sceGameUpdateCheckTitle();
 
 }
diff --git a/docs/dev/debt/libSceGameUpdate.md b/docs/dev/debt/libSceGameUpdate.md
index f00df0b638..bd539a1130 100644
--- a/docs/dev/debt/libSceGameUpdate.md
+++ b/docs/dev/debt/libSceGameUpdate.md
@@ -4,6 +4,10 @@
 
 - [sceGameUpdateCreateRequest, sceGameUpdateCheck](../../../core/libs/prx/libSceGameUpdate/Export.cpp) (libSceGameUpdate) - requests are kept in the module's 8 slots with ids from `0x20000000` (a ninth returns `0x80412806`, an aborted request's Check `0x80412807`), as [prosper](https://github.com/mattias800/prosper) reads the PS5 3.20 `libSceGameUpdate.sprx`. Check never asks a patch service: it always answers no update (`found` and the byte after it cleared, the rest of the result untouched, return 0), which is what the module returns when its service reports `0x80412883`; KytyPS5 also answers no update. What the service returns on an offline console is not measured. The answer only decides whether a title offers a patch. PPSA22408 aborted on the throw in sceGameUpdateCreateRequest at its title screen. Closes when: measured on a PS5
 
+### Unknown function info
+
+- [sceGameUpdateCheckTitle](../../../core/libs/prx/libSceGameUpdate/Export.cpp) has an unknown signature and behaviour. The parameterless `int` declaration is an import-resolution placeholder, not a confirmed ABI signature, and every call throws through `NotImplemented_nid_no_patch`. Only its name and NID `sGNKn-jXzHQ` are established by the [13.60 export inventory](https://github.com/xdCloudy/PS5-13.60-Function-Stub-Library/blob/bfec40deb4c47a17d7603ee2bc79aa6862c0c56b/data/firmware-13.60/libscegameupdate-16da6af946.jsonl); not measured on a console.
+
 ### Functional
 
 - [libSceGameUpdate](../../../core/libs/prx/libSceGameUpdate/Export.cpp): initialization tracks host state but does not connect the patch service. Entitlement version lookup throws.