diff --git a/core/libs/prx/libSceAudioOut/src/AudioOut.cpp b/core/libs/prx/libSceAudioOut/src/AudioOut.cpp
index 4459dc8152..44cb922956 100644
--- a/core/libs/prx/libSceAudioOut/src/AudioOut.cpp
+++ b/core/libs/prx/libSceAudioOut/src/AudioOut.cpp
@@ -663,6 +663,10 @@ int APS5_VABI sceAudioOutSysOpen(int userId, std::uint32_t mode) {
     return allocatePort(PORT_TYPE_SYS, SYS_PORT_SAMPLES, SYS_PORT_FRAME_RATE, Format::S16_8Ch);
 }
 
+int APS5_VABI sceAudioOutSetMainOutput() {
+    return 0;
+}
+
 int APS5_VABI sceAudioOutSetMixLevelPadSpk(int handle, std::uint32_t mixLevel) {
     std::lock_guard<std::mutex> lock(g_mutex);
     Port* port = getPort(handle);
diff --git a/core/libs/prx/libSceAudioOut/src/Unimplemented.cpp b/core/libs/prx/libSceAudioOut/src/Unimplemented.cpp
index 1e44d76aa6..55134a8ef6 100644
--- a/core/libs/prx/libSceAudioOut/src/Unimplemented.cpp
+++ b/core/libs/prx/libSceAudioOut/src/Unimplemented.cpp
@@ -129,11 +129,6 @@ int APS5_VABI sceAudioOutGetFocusEnablePid(void) {
     return 0;
 }
 
-int APS5_VABI sceAudioOutSetMainOutput(void) {
-    NotImplemented_nid_no_patch(__func__);
-    return 0;
-}
-
 int APS5_VABI sceAudioOutSetVolumeDown(void) {
     NotImplemented_nid_no_patch(__func__);
     return 0;
diff --git a/core/libs/prx/libSceAudioOut/tests/AudioOutSys.cpp b/core/libs/prx/libSceAudioOut/tests/AudioOutSys.cpp
index 73ea859c0b..6c8f9561ee 100644
--- a/core/libs/prx/libSceAudioOut/tests/AudioOutSys.cpp
+++ b/core/libs/prx/libSceAudioOut/tests/AudioOutSys.cpp
@@ -46,6 +46,10 @@ int main() {
     Require(Throws([] { sceAudioOutSysConfigureOutput(1, 0, 4, 1, 0); }), "another mode throws");
     Require(Throws([] { sceAudioOutSysConfigureOutput(1, 0, 5, 2, 0); }), "another target throws");
 
+    int mainOutput = -1;
+    Require(!Throws([&mainOutput] { mainOutput = sceAudioOutSetMainOutput(); }), "sceAudioOutSetMainOutput does not throw");
+    Require(mainOutput == 0, "sceAudioOutSetMainOutput returns 0");
+
     Require(sceAudioOutSysClose(truehd) == 0, "close the first Sys port");
     Require(Throws([truehd] { sceAudioOutSysClose(truehd); }), "a closed Sys port throws");
     const int ex = sceAudioOutExOpen(SYSTEM_USER, 0);
diff --git a/docs/dev/debt/libSceAudioOut.md b/docs/dev/debt/libSceAudioOut.md
index edab686a12..d11e3678ee 100644
--- a/docs/dev/debt/libSceAudioOut.md
+++ b/docs/dev/debt/libSceAudioOut.md
@@ -4,6 +4,7 @@
 
 - [sceAudioOut2LoTerminate](../../../core/libs/prx/libSceAudioOut/src/AudioOut2Low.cpp) (libSceAudioOut) - returns 0, as the PS5 12.00 module (0x248d0) does whether or not the low-latency service runs. The module disconnects from the audio server and clears the service tables; here `sceAudioOut2LoInit` starts no service and open contexts and ports are left as they are
 - [sceAudioOutMasteringTerm](../../../core/libs/prx/libSceAudioOut/src/AudioOut2Mastering.cpp) (libSceAudioOut) - returns 0 without doing anything: there is no mastering stage to tear down, and `sceAudioOutMasteringInit` keeps no state. Whether the console fails a Term without a matching Init is unknown
+- [sceAudioOutSetMainOutput](../../../core/libs/prx/libSceAudioOut/src/AudioOut.cpp) (libSceAudioOut) - returns 0 and does nothing, as the console function does on firmware 12.70: [PS5-Audio-Passthrough-Research](https://github.com/sainsaji/PS5-Audio-Passthrough-Research/blob/cf3c921d79bf00db4847f31b68a7bd95a8037cd7/docs/FINDINGS.md#L25) reads that export as `xor eax,eax; ret`. The export reads no argument, so its parameters stay unknown; other firmware versions are unverified
 
 ### Unknown function info
 
@@ -57,7 +58,6 @@
 - [sceAudioOutSetCaesarVolume](../../../core/libs/prx/libSceAudioOut/src/Unimplemented.cpp) (libSceAudioOut) - unknown signature
 - [sceAudioOutSetHeadphoneOutMode](../../../core/libs/prx/libSceAudioOut/src/Unimplemented.cpp) (libSceAudioOut) - unknown signature
 - [sceAudioOutGetFocusEnablePid](../../../core/libs/prx/libSceAudioOut/src/Unimplemented.cpp) (libSceAudioOut) - unknown signature
-- [sceAudioOutSetMainOutput](../../../core/libs/prx/libSceAudioOut/src/Unimplemented.cpp) (libSceAudioOut) - unknown signature
 - [sceAudioOutSetVolumeDown](../../../core/libs/prx/libSceAudioOut/src/Unimplemented.cpp) (libSceAudioOut) - unknown signature
 - [sceAudioOutSetChatBalance](../../../core/libs/prx/libSceAudioOut/src/Unimplemented.cpp) (libSceAudioOut) - unknown signature
 - [sceAudioOutSetRecMode](../../../core/libs/prx/libSceAudioOut/src/Unimplemented.cpp) (libSceAudioOut) - unknown signature