diff --git a/core/hw/sh4/dyna/decoder.cpp b/core/hw/sh4/dyna/decoder.cpp
index e0e4e401e..742216508 100644
--- a/core/hw/sh4/dyna/decoder.cpp
+++ b/core/hw/sh4/dyna/decoder.cpp
@@ -1057,6 +1057,7 @@ bool dec_DecodeBlock(RuntimeBlockInfo* rbi,u32 max_cycles)
 					u32 op;
 					if (!mmu_enabled())
 						op = IReadMem16(state.cpu.rpc);
+#ifndef NO_MMU
 					else
 					{
 						u32 exception_occurred;
@@ -1064,6 +1065,7 @@ bool dec_DecodeBlock(RuntimeBlockInfo* rbi,u32 max_cycles)
 						if (exception_occurred)
 							return false;
 					}
+#endif
 					if (op==0 && state.cpu.is_delayslot)
 					{
 						printf("Delayslot 0 hack!\n");
@@ -1157,7 +1159,7 @@ _end:
 	if (settings.dynarec.idleskip)
 	{
 		//Experimental hash-id based idle skip
-		if (strstr(idle_hash,blk->hash(false,true)))
+		if (strstr(idle_hash,blk->hash(false,true)))	// FIXME don't hash temp blocks. Use xxhash instead of sha1
 		{
 			//printf("IDLESKIP: %08X reloc match %s\n",blk->addr,blk->hash(false,true));
 			blk->guest_cycles=max_cycles*100;
diff --git a/core/rec-ARM64/rec_arm64.cpp b/core/rec-ARM64/rec_arm64.cpp
index d0a829c5d..343a80639 100644
--- a/core/rec-ARM64/rec_arm64.cpp
+++ b/core/rec-ARM64/rec_arm64.cpp
@@ -290,6 +290,7 @@ RuntimeBlockInfo* ngen_AllocateBlock()
 template<typename T>
 static T ReadMemNoEx(u32 addr, u32 pc)
 {
+#ifndef NO_MMU
 	u32 ex;
 	T rv = mmu_ReadMemNoEx<T>(addr, &ex);
 	if (ex)
@@ -301,11 +302,15 @@ static T ReadMemNoEx(u32 addr, u32 pc)
 		longjmp(jmp_env, 1);
 	}
 	return rv;
+#else
+	return (T)0;	// not used
+#endif
 }
 
 template<typename T>
 static void WriteMemNoEx(u32 addr, T data, u32 pc)
 {
+#ifndef NO_MMU
 	u32 ex = mmu_WriteMemNoEx<T>(addr, data);
 	if (ex)
 	{
@@ -315,6 +320,7 @@ static void WriteMemNoEx(u32 addr, T data, u32 pc)
 			spc = pc;
 		longjmp(jmp_env, 1);
 	}
+#endif
 }
 
 static u32 interpreter_fallback(u16 op, u32 pc)
@@ -1619,7 +1625,7 @@ private:
 		TailCallRuntime(ngen_blockcheckfail);
 
 		Bind(&blockcheck_success);
-/*
+
 		if (mmu_enabled() && block->has_fpu_op)
 		{
 			Label fpu_enabled;
@@ -1635,7 +1641,6 @@ private:
 
 			Bind(&fpu_enabled);
 		}
-*/
 	}
 
 	void shil_param_to_host_reg(const shil_param& param, const Register& reg)
diff --git a/core/rec-x64/rec_x64.cpp b/core/rec-x64/rec_x64.cpp
index 9c413ed8a..9723ffc43 100644
--- a/core/rec-x64/rec_x64.cpp
+++ b/core/rec-x64/rec_x64.cpp
@@ -224,6 +224,7 @@ static u32 exception_raised;
 template<typename T>
 static T ReadMemNoEx(u32 addr, u32 pc)
 {
+#ifndef NO_MMU
 	T rv = mmu_ReadMemNoEx<T>(addr, &exception_raised);
 	if (exception_raised)
 	{
@@ -235,11 +236,16 @@ static T ReadMemNoEx(u32 addr, u32 pc)
 		longjmp(jmp_env, 1);
 	}
 	return rv;
+#else
+	// not used
+	return (T)0;
+#endif
 }
 
 template<typename T>
 static void WriteMemNoEx(u32 addr, T data, u32 pc)
 {
+#ifndef NO_MMU
 	exception_raised = mmu_WriteMemNoEx<T>(addr, data);
 	if (exception_raised)
 	{
@@ -250,6 +256,7 @@ static void WriteMemNoEx(u32 addr, T data, u32 pc)
 			spc = pc;
 		longjmp(jmp_env, 1);
 	}
+#endif
 }
 
 static void interpreter_fallback(u16 op, OpCallFP *oph, u32 pc)