diff --git a/synth.sh b/synth.sh
index 05e20c0..6344227 100755
--- a/synth.sh
+++ b/synth.sh
@@ -1,177 +1,208 @@
 #!/bin/bash
 
 BBDD_SCRIPT="yosys/bbdd_synth_muxxor.ys"
 BDD_SCRIPT="yosys/bdd_synth.ys"
 MUXIG_SCRIPT="yosys/muxig_synth.ys"
 TEMP_DIR="temp"
 LIBERTY_FILE="liberty/nem_thesis.lib"
 TIMEOUT="2m" #1 minute timeout for now
 TECHMAP_BBDD="yosys/techmap_bbdd.v"
 TABLE_SIZE="300000"
 MAX_INPUTS=0 # 0 disables partitioning, i.e. one diagram over all inputs
 
 print_options(){
   echo "(1) Synthesis Verilog file with bbdd optimization"
   echo "(2) Synthesis Verilog file with bdd optimization"
   echo "(3) Synthesis Verilog file with muxig optimization"
   echo "(e) Exit"
 }
 
 safe_path() {
   local unsafe_path="$1"
   echo "$(printf '%s\n' "$unsafe_path" | sed 's/[&/\]/\\&/g')"
 }
 
 process_input() {
   file_name=$(basename "$file_path") # with extension
   file_base="${file_name%.*}" # without
 
   # get top module name
   read -p "top module [default=${file_base}] " top_module
   top_module=${top_module:-${file_base}}
 
   #safe_file_path=$(printf '%s\n' "$file_path" | sed 's/[&/\]/\\&/g')
   safe_file_path=$(safe_path "$file_path")
   #safe_techmap_path=$(printf '%s\n' "$TECHMAP_BBDD" | sed 's/[&/\]/\\&/g')
 }
 
 run_yosys() {
   # Run yosys
   if $nosat; then
     sat_replacement="#"   # comment out {{SAT}}
   else
     sat_replacement=""    # replace {{SAT}} with nothing
   fi
   # options handed to the converter; the bbdd template picks them up through
   # {{CONV_FLAGS}}. convert_bdd takes no options, and its template has no
   # placeholder, so the substitution is a no-op there.
   conv_flags="-t $TABLE_SIZE"
   if [ "$MAX_INPUTS" -gt 0 ] 2>/dev/null; then
     conv_flags="$conv_flags -n $MAX_INPUTS"
   fi
   echo "Synthesising $file_base"
   sed -e "s/{{VERILOG_FILE}}/$safe_file_path/g" \
       -e "s/{{TEMP_DIR}}/$TEMP_DIR/g" \
       -e "s/{{TOP_MODULE}}/$top_module/g" \
       -e "s/{{BASE_NAME}}/$file_base/g" \
       -e "s/{{TECHMAP_BBDD}}/$safe_techmap_path/g" \
       -e "s/{{LIBERTY_FILE}}/$safe_liberty_path/g" \
       -e "s/{{OUT_DIR}}/$safe_out_path/g" \
       -e "s/{{TIMEOUT}}/$TIMEOUT/g" \
       -e "s/{{SAT}}/$sat_replacement/g" \
       -e "s/{{CONV_FLAGS}}/$(safe_path "$conv_flags")/g" \
       "$yosys_script" > "$TEMP_DIR/${file_base}_synth.ys"
+  if $STRIP_NOSCOPEINFO; then
+    sed -i 's/flatten -noscopeinfo/flatten/' "$TEMP_DIR/${file_base}_synth.ys"
+  fi
   mkdir -p ${out_dir}/${file_base}/
   /usr/bin/time -f "Time: %E\nCPU: %P\nMemory: %M KB" -o ${out_dir}/${file_base}/yosys_${opt_name}_time.txt yosys${yosys_flags} ${TEMP_DIR}/${file_base}_synth.ys
   if [ -e ${out_dir}/${file_base} ]; then
-    python ./yosys/print_summary.py ${out_dir}/${file_base}
+    # The summary is a convenience on top of a finished run, so a missing
+    # interpreter or an uninstalled plotting dependency must not be reported
+    # as if the synthesis itself had failed.
+    if [ -n "$PYTHON" ]; then
+      "$PYTHON" ./yosys/print_summary.py ${out_dir}/${file_base} \
+        || echo "[WARN] print_summary.py failed; results are still in ${out_dir}/${file_base}"
+    else
+      echo "[WARN] no python interpreter found; skipping print_summary.py"
+    fi
   else
     echo "${file_base} did not finish in time"
   fi 
 }
 
 synth_verilog() {
   local yosys_script="$1"
   local opt_name="$2"
   if ! $verbose; then
     yosys_flags=" -q" # is quite mode
   else
     yosys_flags=""
   fi
   safe_techmap_path=$(safe_path "$TECHMAP_BBDD")
   safe_liberty_path=$(safe_path "$LIBERTY_FILE")
   echo "Using script: $yosys_script"
   read -e -p 'Input file path: ' file_path 
   # Get Output Dir
   read -e -p 'Output directory: ' out_dir
   safe_out_path=$(safe_path "$out_dir")
   out_dir="${out_dir%/}/"
   if [ -f "$file_path" ]; then 
     process_input
     run_yosys
     if ! $nocleanup; then
       rm ${TEMP_DIR}/${file_base}_synth.ys
       rm ${TEMP_DIR}/${file_base}.blif
       rm -f ${TEMP_DIR}/${file_base}_bbdd.blif
       rm -f ${TEMP_DIR}/${file_base}_bdd.blif
     fi
     exit
   elif [ -d "$file_path" ]; then
     # extend / if not present
     file_path="${file_path%/}/"
     for file in "$file_path"*.v; do
       if [ -e "$file" ]; then
         safe_file_path=$(safe_path "$file")
         file_name=$(basename "$file") # with extension
         file_base="${file_name%.*}" # without
         top_module="$file_base"
         yosys_flags=" -q"
         run_yosys
         if ! $nocleanup; then
           rm ${TEMP_DIR}/${file_base}_synth.ys
           rm ${TEMP_DIR}/${file_base}.blif
           rm -f ${TEMP_DIR}/${file_base}_bbdd.blif
           rm -f ${TEMP_DIR}/${file_base}_bdd.blif
         fi
       fi
     done
     exit
   else
     echo "[ERROR] File ${file_path} does not exist"
   fi 
 }
 
 handle_selection() {
     case "$1" in
         1) synth_verilog $BBDD_SCRIPT "bbdd";;
         2) synth_verilog $BDD_SCRIPT "bdd";;
         3) synth_verilog $MUXIG_SCRIPT "muxig";;
         e) echo "Exiting..."; exit 0 ;;
         *) echo "Invalid option. Please try again." ;;
     esac
 }
 
 # Initialize booleans as false
 nocleanup=false
 nosat=false
 verbose=false
 
 # Parse flags
 while [[ $# -gt 0 ]]; do
   case "$1" in
     -nocleanup)
       nocleanup=true
       shift
       ;;
     -nosat)
       nosat=true
       shift
       ;;
     -v)
       verbose=true
       shift
       ;;
     -n)
       MAX_INPUTS="$2"
       shift 2
       ;;
     *)
       echo "Unknown option: $1"
       echo "Usage: $0 [-nocleanup] [-nosat] [-v] [-n MAX_INPUTS]"
       exit 1
       ;;
   esac
 done
 
+# print_summary.py is invoked through whichever interpreter this host actually
+# has; `python` is absent on distributions that ship only python3.
+PYTHON=""
+for candidate in python3 python; do
+  if command -v "$candidate" >/dev/null 2>&1; then
+    PYTHON="$candidate"
+    break
+  fi
+done
+
+# yosys 0.40 added `flatten -noscopeinfo`; on older yosys the flag is a hard
+# error ("Command syntax error: Unknown option"), and plain `flatten` is
+# equivalent there because no $scopeinfo cells are produced in the first place.
+# Detect once and patch the rendered script if needed.
+STRIP_NOSCOPEINFO=false
+if ! yosys -qp "help flatten" 2>/dev/null | grep -q -- "-noscopeinfo"; then
+  STRIP_NOSCOPEINFO=true
+  echo "[INFO] yosys $(yosys -V 2>/dev/null | awk '{print $2}') has no 'flatten -noscopeinfo'; stripping the flag"
+fi
+
 # get input file
 mkdir -p $TEMP_DIR 
 
 while true; do
   if [ "$nosat" = false ]; then
     echo "Satisfiability check is enabled"
   fi
   print_options
   read -p "Enter your choice [1-3]: " choice
   handle_selection "$choice"
   echo ""
 done