diff --git a/Core/HLE/sceNet.cpp b/Core/HLE/sceNet.cpp
index bd6506d67b..640c6a509f 100644
--- a/Core/HLE/sceNet.cpp
+++ b/Core/HLE/sceNet.cpp
@@ -1065,12 +1065,24 @@ static int sceNetInit(MIPSState *mips, u32 poolSize, u32 calloutPri, u32 callout
 
 // Free(delete) thread info / data. 
 // Normal usage: sceKernelDeleteThread followed by sceNetFreeThreadInfo with the same threadID as argument
+// Both take any thread, also the current one or one that has ended (pspautotests net/inet/offline).
+static bool IsThreadID(SceUID thid) {
+	int type = 0;
+	return thid != 0 && kernelObjects.GetIDType(thid, &type) && type == SCE_KERNEL_TMID_Thread;
+}
+
 static int sceNetFreeThreadinfo(SceUID thid) {
+	if (!IsThreadID(thid)) {
+		return hleLogError(Log::sceNet, 0x80410104, "not a thread");
+	}
 	return hleLogError(Log::sceNet, 0, "UNIMPL");
 }
 
 // Abort a thread.
 static int sceNetThreadAbort(SceUID thid) {
+	if (!IsThreadID(thid)) {
+		return hleLogError(Log::sceNet, 0x80410104, "not a thread");
+	}
 	return hleLogError(Log::sceNet, 0, "UNIMPL");
 }
 
@@ -1184,7 +1196,7 @@ static void sceNetEtherStrton(u32 bufferPtr, u32 macPtr) {
 static int sceNetGetMallocStat(u32 statPtr) {
 	auto stat = PSPPointer<SceNetMallocStat>::Create(statPtr);
 	if (!stat.IsValid())
-		return hleLogError(Log::sceNet, 0, "invalid address");
+		return hleLogError(Log::sceNet, 0x80410103, "invalid address");
 
 	*stat = netMallocStat;
 	stat.NotifyWrite("sceNetGetMallocStat");
@@ -1497,6 +1509,10 @@ static int NetApctl_AddHandler(u32 handlerPtr, u32 handlerArg) {
 // TODO: Should we allow the same handler to be added more than once?
 static u32 sceNetApctlAddHandler(u32 handlerPtr, u32 handlerArg) {
 	INFO_LOG(Log::sceNet, "%s(%08x, %08x)", __FUNCTION__, handlerPtr, handlerArg);
+	// A game gets two (pspautotests net/inet/offline).
+	if (apctlHandlers.size() >= MAX_APCTL_GAME_HANDLERS) {
+		return hleLogError(Log::sceNet, 0x80410A0F, "too many handlers");
+	}
 	return NetApctl_AddHandler(handlerPtr, handlerArg);
 }
 
@@ -1513,6 +1529,14 @@ static int NetApctl_DelHandler(u32 handlerID) {
 
 static int sceNetApctlDelHandler(u32 handlerID) {
 	INFO_LOG(Log::sceNet, "%s(%d)", __FUNCTION__, handlerID);
+	// An ID that can't be a handler's (100, -1) and a free one give different errors
+	// (pspautotests net/inet/offline). Where the range ends is inferred from the handler limit.
+	if (handlerID >= MAX_APCTL_GAME_HANDLERS) {
+		return hleLogError(Log::sceNet, 0x80410A82, "bad handler id");
+	}
+	if (apctlHandlers.find(handlerID) == apctlHandlers.end()) {
+		return hleLogError(Log::sceNet, SCE_NET_APCTL_ERROR_INVALID_ID, "no such handler");
+	}
 	return NetApctl_DelHandler(handlerID);
 }
 
@@ -1575,7 +1599,7 @@ static int sceNetApctlGetState(u32 pStateAddr) {
 		return hleLogDebug(Log::sceNet, 0);
 	}
 
-	return hleLogError(Log::sceNet, -1, "apctl invalid arg"); // 0x8002013A or ERROR_NET_WLAN_INVALID_ARG ?
+	return hleLogError(Log::sceNet, 0x80410A03, "apctl invalid arg"); // pspautotests net/inet/offline
 }
 
 // This one logs like a syscall because it's called at the end of some.
@@ -1601,8 +1625,9 @@ int NetApctl_GetBSSDescIDListUser(u32 sizeAddr, u32 bufAddr) {
 	const int userInfoSize = 8; // 8 bytes per entry (next address + entry id)
 	// Faking 4 entries, games like MGS:PW Recruit will need to have a different AP for each entry
 	int entries = 4;
-	if (!Memory::IsValid4AlignedAddress(sizeAddr) || !Memory::IsValidAddress(bufAddr))
-		return hleLogError(Log::sceNet, -1, "apctl invalid arg"); // 0x8002013A or ERROR_NET_WLAN_INVALID_ARG ?
+	// A NULL buffer asks for the size (pspautotests net/inet/offline).
+	if (!Memory::IsValid4AlignedAddress(sizeAddr) || (bufAddr != 0 && !Memory::IsValidAddress(bufAddr)))
+		return hleLogError(Log::sceNet, 0x80410A03, "apctl invalid arg");
 
 	int size = Memory::ReadUnchecked_U32(sizeAddr);
 	// Return size required
@@ -1748,16 +1773,14 @@ static int sceNetApctlDelInternalHandler(u32 handlerID) {
 
 static int sceNetApctlAddInternal03Handler(u32 handlerPtr, u32 handlerArg) {
 	ERROR_LOG(Log::sceNet, "UNIMPL %s(%08x, %08x)", __FUNCTION__, handlerPtr, handlerArg);
-	// This seems to be a 3rd kind of handler
-	// Simple forward, don't need to use hleCall
-	return sceNetApctlAddHandler(handlerPtr, handlerArg);
+	// This seems to be a 3rd kind of handler. The game handler limit doesn't apply.
+	return NetApctl_AddHandler(handlerPtr, handlerArg);
 }
 
 static int sceNetApctlDelInternal03Handler(u32 handlerID) {
 	ERROR_LOG(Log::sceNet, "UNIMPL %s(%i)", __FUNCTION__, handlerID);
 	// This seems to be a 3rd kind of handler
-	// Simple forward, don't need to use hleCall
-	return sceNetApctlDelHandler(handlerID);
+	return NetApctl_DelHandler(handlerID);
 }
 
 static int sceNetApctl_lib2_69745F0A(int handlerId) {
diff --git a/Core/HLE/sceNet.h b/Core/HLE/sceNet.h
index 8851f219b4..5418efa2fb 100644
--- a/Core/HLE/sceNet.h
+++ b/Core/HLE/sceNet.h
@@ -38,6 +38,7 @@
 
 // TODO: Determine how many handlers we can actually have
 const size_t MAX_APCTL_HANDLERS = 32;
+const size_t MAX_APCTL_GAME_HANDLERS = 2; // Through sceNetApctlAddHandler (pspautotests net/inet/offline)
 
 typedef void(*sceNetApctlHandler)(int oldState, int newState, int event, int error, void* pArg);