diff --git a/VERSION b/VERSION
index b707fed..d683ffe 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.5.172
+1.5.173
diff --git a/tcltk/netgen.tcl.in b/tcltk/netgen.tcl.in
index e3ac928..69aff27 100644
--- a/tcltk/netgen.tcl.in
+++ b/tcltk/netgen.tcl.in
@@ -389,8 +389,23 @@ proc netgen::lvs { name1 name2 {setupfile setup.tcl} {logfile comp.out} args} {
 	 puts stdout "Treating empty subcircuits as black-box cells"
 	 netgen::model blackbox on
       } elseif {[string first "-noflatten=" $arg] == 0} {
-	 set noflat [string trim [string range $arg 11 end] \"\{\}]
-	 puts stdout "Will not flatten these subcells: $noflat"
+	 set value [string range $arg 11 end]
+	 # If argument is a filename then read the list of cells from it;
+	 # otherwise, argument is the list of files itself in quotes or
+	 # braces.
+	 if {![catch {file exists $value}]} {
+	    if {![catch {open $value r} fnf]} {
+		while {[gets $fnf line] >= 0} {
+		    lappend noflat $line
+		}
+		close $fnf
+	    } else {
+	       puts stderr "Cannot open file $value for reading cell list."
+	    }
+	 } else {
+	    set noflat [string trim $value \"\{\}]
+	    puts stdout "Will not flatten these subcells: $noflat"
+	 }
       }
    }