diff --git a/Makefile b/Makefile
index 4d5e7e6..4c6f72a 100644
--- a/Makefile
+++ b/Makefile
@@ -18,13 +18,16 @@ clean:
 clean_dut:
 	cd dut && ls | grep -v __init__.py | xargs rm -rf
 
-test_all:
+clean_rtl:
+	cd rtl && ls | grep -v README.md | xargs rm -rf
+
+test_all: dut
 	@python3 run.py --config $(CFG) $(KV) -- $(REPORT) -vs ut_*/ $(args)
 
-test:
+test: dut
 	@python3 run.py --config $(CFG) $(KV) -- $(REPORT) -vs $(target) $(args)
 
-dut:
+dut: rtl
 	@python3 run.py --config $(CFG) --build $(DUTS) $(args)
 
 rtl:
diff --git a/comm/functions.py b/comm/functions.py
index 9bf3de5..52cf7b0 100644
--- a/comm/functions.py
+++ b/comm/functions.py
@@ -180,10 +180,20 @@ def download_rtl(base_url, out_dir, version="latest"):
         use_rtl(base_url.split("/")[-1], out_dir)
     return True
 
+def _build_dut(d, cfg):
+    try:
+        module = importlib.import_module(f"scripts.{d}")
+        if not module.build(cfg):
+            warning(f"Build scripts/{d}.py failed")
+        else:
+            info(f"Build scripts/{d}.py success")
+    except Exception as e:
+        warning(f"Failed to build {d}, error: {e}\n{traceback.format_exc()}")
 
 def build_dut(duts, cfg):
     target_duts = [d.strip() for d in duts.split(",")]
     if len(target_duts) == 0:
+        warning(f"No dut to build for: {duts}")
         return
     prefix = "build_ut_"
     build_modules = [f.replace(".py", "") for f in 
@@ -199,16 +209,11 @@ def build_dut(duts, cfg):
     if len(dut_to_build) == 0:
         warning(f"No dut to build for: {duts}")
         return
-    for d in dut_to_build:
-        debug(f"Build {d}")
-        try:
-            module = importlib.import_module(f"scripts.{d}")
-            if not module.build(cfg):
-                warning(f"Build scripts/{d}.py failed")
-            else:
-                info(f"Build scripts/{d}.py success")
-        except Exception as e:
-            warning(f"Failed to build {d}, error: {e}\n{traceback.format_exc()}")
+    import multiprocessing
+    pool = multiprocessing.Pool()
+    pool.starmap(_build_dut, [(d, cfg) for d in dut_to_build])
+    pool.close()
+    pool.join()
 
 
 def replace_default_vars(input_str, cfg):
diff --git a/ut_backend/ctrl_block/decode/env/decode_wrapper.py b/ut_backend/ctrl_block/decode/env/decode_wrapper.py
index 4748fb8..2bf0dd1 100644
--- a/ut_backend/ctrl_block/decode/env/decode_wrapper.py
+++ b/ut_backend/ctrl_block/decode/env/decode_wrapper.py
@@ -167,7 +167,8 @@ def Reset(self):
     def Input_instruction(self, i, valid, instr, isRVC, brType, isCall, isRet, pred_taken, instr_ex):
         self.input_inst[i].valid.value = valid
         self.input_inst[i].bits_instr.value = instr
-        self.input_inst[i].bits_foldpc.value = 0
+        if hasattr(self.input_inst[i], "bits_foldpc"):
+            self.input_inst[i].bits_foldpc.value = 0
         self.input_inst[i].bits_exceptionVec_2.value = instr_ex
         for j in range(24):
             p = getattr(self.dut, f'io_in_{i}_bits_exceptionVec_{j}', None)