diff --git a/tools/hdltool_unb2b.cfg b/tools/hdltool_unb2b.cfg
index 2afb4650824c39949e6ad638eec83e286498c2f2..b64df2cafcab07946a8ca3862050b2a4a7ab5c39 100644
--- a/tools/hdltool_unb2b.cfg
+++ b/tools/hdltool_unb2b.cfg
@@ -4,7 +4,7 @@ technology_names = ip_arria10_e1sg
 build_dir = $HDL_BUILD_DIR
 tool_name_sim = modelsim
 tool_name_synth = quartus
-model_tech_dir = /home/software/Mentor/10.4/modeltech
+model_tech_dir = /home/software/Mentor/10.4/questasim
 modelsim_search_libraries =
     # arria10 only
     altera_ver lpm_ver sgate_ver altera_mf_ver altera_lnsim_ver twentynm_ver twentynm_hssi_ver twentynm_hip_ver
diff --git a/tools/modelsim/modelsim_version.sh b/tools/modelsim/modelsim_version.sh
index 00b6efe0e2545a77cf0edfea18031369fd0facac..58e29e0ad091be7e95f53ce5294a97b6e9ddecf2 100755
--- a/tools/modelsim/modelsim_version.sh
+++ b/tools/modelsim/modelsim_version.sh
@@ -30,5 +30,9 @@ MODELSIM_VERSION_DIR=${MODELSIM_VERSION}
 #fi
 
 # Must not define MODEL_TECH, because it gets defined when the tool starts. Therefore define MODEL_TECH_DIR to denote the modeltech version directory
-export MODEL_TECH_DIR=/home/software/Mentor/${MODELSIM_VERSION_DIR}/modeltech
+if [ "${MODELSIM_VERSION}" = "10.4" ]; then
+    export MODEL_TECH_DIR=/home/software/Mentor/${MODELSIM_VERSION_DIR}/questasim
+else
+    export MODEL_TECH_DIR=/home/software/Mentor/${MODELSIM_VERSION_DIR}/modeltech
+fi
 export VSIM_DIR=$MODEL_TECH_DIR/linux_x86_64