diff --git a/rules/pulpos/default_rules.mk b/rules/pulpos/default_rules.mk
index 07625c4..554c484 100644
--- a/rules/pulpos/default_rules.mk
+++ b/rules/pulpos/default_rules.mk
@@ -9,6 +9,7 @@ endif
 
 platform ?= rtl
 
+export ETH_QUESTA_PREFIX ?= ""
 
 ifdef PULP_RUNTIME_GCC_TOOLCHAIN
 PULP_CC := $(PULP_RUNTIME_GCC_TOOLCHAIN)/bin/$(PULP_CC)
@@ -222,10 +223,10 @@ run: $(TARGET_BUILD_DIR)/modelsim.ini  $(TARGET_BUILD_DIR)/boot $(TARGET_BUILD_D
 
 ifdef gui
 #	cd $(TARGET_BUILD_DIR) && export VSIM_RUNNER_FLAGS="+ENTRY_POINT=0x1c008080 -gLOAD_L2=JTAG -dpicpppath /usr/bin/g++ -permit_unmatched_virtual_intf -gBAUDRATE=115200" && export VOPT_ACC_ENA="YES" && vsim -64 -do 'source $(VSIM_PATH)/tcl_files/config/run_and_exit.tcl' -do 'source $(VSIM_PATH)/tcl_files/run.tcl; '
-	cd $(TARGET_BUILD_DIR) && export VSIM_RUNNER_FLAGS="+ENTRY_POINT=0x1c008080 -gLOAD_L2=JTAG -dpicpppath /usr/bin/g++ -permit_unmatched_virtual_intf -gBAUDRATE=115200" && export VOPT_ACC_ENA="YES" && questa-2020.1 vsim -64 -do 'source $(VSIM_PATH)/tcl_files/config/run_and_exit.tcl' -do 'source $(VSIM_PATH)/tcl_files/run.tcl; '
+	cd $(TARGET_BUILD_DIR) && export VSIM_RUNNER_FLAGS="+ENTRY_POINT=0x1c008080 -gLOAD_L2=JTAG -dpicpppath /usr/bin/g++ -permit_unmatched_virtual_intf -gBAUDRATE=115200" && export VOPT_ACC_ENA="YES" && $(ETH_QUESTA_PREFIX)vsim -64 -do 'source $(VSIM_PATH)/tcl_files/config/run_and_exit.tcl' -do 'source $(VSIM_PATH)/tcl_files/run.tcl; '
 else
 #	cd $(TARGET_BUILD_DIR) && export VSIM_RUNNER_FLAGS="+ENTRY_POINT=0x1c008080 -gLOAD_L2=JTAG -dpicpppath /usr/bin/g++ -permit_unmatched_virtual_intf -gBAUDRATE=115200" && vsim -64 -c -do 'source $(VSIM_PATH)/tcl_files/config/run_and_exit.tcl' -do 'source $(VSIM_PATH)/tcl_files/run.tcl; run_and_exit;'
-	cd $(TARGET_BUILD_DIR) && export VSIM_RUNNER_FLAGS="+ENTRY_POINT=0x1c008080 -gLOAD_L2=JTAG -dpicpppath /usr/bin/g++ -permit_unmatched_virtual_intf -gBAUDRATE=115200" && questa-2020.1 vsim -64 -c -do 'source $(VSIM_PATH)/tcl_files/config/run_and_exit.tcl' -do 'source $(VSIM_PATH)/tcl_files/run.tcl; run_and_exit;'
+	cd $(TARGET_BUILD_DIR) && export VSIM_RUNNER_FLAGS="+ENTRY_POINT=0x1c008080 -gLOAD_L2=JTAG -dpicpppath /usr/bin/g++ -permit_unmatched_virtual_intf -gBAUDRATE=115200" && $(ETH_QUESTA_PREFIX)vsim -64 -c -do 'source $(VSIM_PATH)/tcl_files/config/run_and_exit.tcl' -do 'source $(VSIM_PATH)/tcl_files/run.tcl; run_and_exit;'
 endif
 
 endif