diff --git a/src/3rdparty/masm/masm-defs.pri b/src/3rdparty/masm/masm-defs.pri
index 8265bba617..255c490fd7 100644
--- a/src/3rdparty/masm/masm-defs.pri
+++ b/src/3rdparty/masm/masm-defs.pri
@@ -1,4 +1,4 @@
-DEFINES += V4_ENABLE_JIT
+!ios:!if(win*:isEqual(QT_ARCH, "x86_64")): DEFINES += V4_ENABLE_JIT
 
 DEFINES += WTF_EXPORT_PRIVATE="" JS_EXPORT_PRIVATE=""
 
@@ -6,11 +6,11 @@ win*: DEFINES += NOMINMAX
 
 DEFINES += ENABLE_LLINT=0
 DEFINES += ENABLE_DFG_JIT=0
-DEFINES += ENABLE_JIT=1
 DEFINES += ENABLE_JIT_CONSTANT_BLINDING=0
 DEFINES += ENABLE_ASSEMBLER=1
-DEFINES += ENABLE_YARR_JIT=1
 DEFINES += BUILDING_QT__
+DEFINES += ENABLE_YARR_JIT=1
+DEFINES += ENABLE_JIT=1
 
 INCLUDEPATH += $$PWD/jit
 INCLUDEPATH += $$PWD/assembler
diff --git a/tools/v4/main.cpp b/tools/v4/main.cpp
index c4af264e90..5cdd4dfdb9 100644
--- a/tools/v4/main.cpp
+++ b/tools/v4/main.cpp
@@ -276,7 +276,12 @@ int main(int argc, char *argv[])
         use_llvm_compiler,
         use_llvm_runtime,
         use_llvm_jit
-    } mode = use_masm;
+    } mode;
+#ifdef V4_ENABLE_JIT
+    mode = use_masm;
+#else
+    mode = use_moth;
+#endif
 
 #ifdef QMLJS_WITH_LLVM
     QQmlJS::LLVMOutputType fileType = QQmlJS::LLVMOutputObject;