diff --git a/Core/HLE/scePsmf.cpp b/Core/HLE/scePsmf.cpp
index 719df3376e..6687a2b280 100644
--- a/Core/HLE/scePsmf.cpp
+++ b/Core/HLE/scePsmf.cpp
@@ -764,9 +764,10 @@ u32 scePsmfGetEPWithId(u32 psmfStruct, int epid, u32 entryAddr)
 		return ERROR_PSMF_NOT_FOUND;
 	}
 	DEBUG_LOG(ME, "scePsmfGetEPWithId(%08x, %i, %08x)", psmfStruct, epid, entryAddr);
+
 	if (epid < 0 || epid >= (int)psmf->EPMap.size()) {
-		// TODO: Just a guess.
-		return ERROR_PSMF_INVALID_TIMESTAMP;
+		ERROR_LOG(ME, "scePsmfGetEPidWithTimestamp(%08x, %i): invalid id", psmfStruct, epid);
+		return ERROR_PSMF_INVALID_ID;
 	}
 	if (Memory::IsValidAddress(entryAddr)) {
 		Memory::WriteStruct(entryAddr, &psmf->EPMap[epid]);
@@ -782,14 +783,16 @@ u32 scePsmfGetEPWithTimestamp(u32 psmfStruct, u32 ts, u32 entryAddr)
 		return ERROR_PSMF_NOT_FOUND;
 	}
 	DEBUG_LOG(ME, "scePsmfGetEPWithTimestamp(%08x, %i, %08x)", psmfStruct, ts, entryAddr);
+
 	if (ts < psmf->presentationStartTime) {
+		ERROR_LOG(ME, "scePsmfGetEPidWithTimestamp(%08x, %i): invalid timestamp", psmfStruct, ts);
 		return ERROR_PSMF_INVALID_TIMESTAMP;
 	}
 
 	int epid = psmf->FindEPWithTimestamp(ts);
 	if (epid < 0 || epid >= (int)psmf->EPMap.size()) {
-		// TODO: Just a guess.
-		return ERROR_PSMF_INVALID_TIMESTAMP;
+		ERROR_LOG(ME, "scePsmfGetEPidWithTimestamp(%08x, %i): invalid id", psmfStruct, epid);
+		return ERROR_PSMF_INVALID_ID;
 	}
 
 	if (Memory::IsValidAddress(entryAddr)) {
@@ -806,14 +809,16 @@ u32 scePsmfGetEPidWithTimestamp(u32 psmfStruct, u32 ts)
 		return ERROR_PSMF_NOT_FOUND;
 	}
 	DEBUG_LOG(ME, "scePsmfGetEPidWithTimestamp(%08x, %i)", psmfStruct, ts);
+
 	if (ts < psmf->presentationStartTime) {
+		ERROR_LOG(ME, "scePsmfGetEPidWithTimestamp(%08x, %i): invalid timestamp", psmfStruct, ts);
 		return ERROR_PSMF_INVALID_TIMESTAMP;
 	}
 
 	int epid = psmf->FindEPWithTimestamp(ts);
 	if (epid < 0 || epid >= (int)psmf->EPMap.size()) {
-		// TODO: Just a guess.
-		return ERROR_PSMF_INVALID_TIMESTAMP;
+		ERROR_LOG(ME, "scePsmfGetEPidWithTimestamp(%08x, %i): invalid id", psmfStruct, epid);
+		return ERROR_PSMF_INVALID_ID;
 	}
 	return epid;
 }