diff --git a/verilog/dv/mprj_por/Makefile b/verilog/dv/mprj_por/Makefile
index 242d99c..5d0825f 100644
--- a/verilog/dv/mprj_por/Makefile
+++ b/verilog/dv/mprj_por/Makefile
@@ -14,7 +14,7 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-## PDK
+## PDK 
 PDK_PATH = $(PDK_ROOT)/sky130A
 
 ## Caravel Pointers
@@ -35,6 +35,7 @@
 GCC_PREFIX?=riscv32-unknown-elf
 
 ## Simulation mode: RTL/GL
+SIM_DEFINES = -DFUNCTIONAL -DSIM
 SIM?=RTL
 
 .SUFFIXES:
@@ -47,12 +48,12 @@
 
 %.vvp: %_tb.v %.hex
 ifeq ($(SIM),RTL)
-	iverilog -DFUNCTIONAL -DSIM -I $(PDK_PATH) \
+	iverilog $(SIM_DEFINES) -I $(PDK_PATH) \
 	-I $(CARAVEL_BEHAVIOURAL_MODELS) -I $(CARAVEL_RTL_PATH) \
 	-I $(UPRJ_BEHAVIOURAL_MODELS)    -I $(UPRJ_RTL_PATH) \
 	$< -o $@ 
 else  
-	iverilog -DFUNCTIONAL -DSIM -DGL -I $(PDK_PATH) \
+	iverilog $(SIM_DEFINES) -DGL -I $(PDK_PATH) \
 	-I $(CARAVEL_BEHAVIOURAL_MODELS) -I $(CARAVEL_RTL_PATH) -I $(CARAVEL_VERILOG_PATH) \
 	-I $(UPRJ_BEHAVIOURAL_MODELS) -I$(UPRJ_RTL_PATH)   -I $(UPRJ_VERILOG_PATH) \
 	$< -o $@ 
@@ -82,6 +83,10 @@
 ifeq (,$(wildcard $(GCC_PATH)/$(GCC_PREFIX)-gcc ))
 	$(error $(GCC_PATH)/$(GCC_PREFIX)-gcc is not found, please export GCC_PATH and GCC_PREFIX before running make)
 endif
+# check for efabless style installation
+ifeq (,$(wildcard $(PDK_ROOT)/sky130A/libs.ref/*/verilog))
+SIM_DEFINES := ${SIM_DEFINES} -DEF_STYLE
+endif
 
 # ---- Clean ----