diff --git a/VERSION b/VERSION
index 9b52297..f7dc9a7 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.0.520
+1.0.521
diff --git a/sky130/custom/scripts/check_density.py b/sky130/custom/scripts/check_density.py
index 4358ed3..18556bd 100755
--- a/sky130/custom/scripts/check_density.py
+++ b/sky130/custom/scripts/check_density.py
@@ -196,7 +196,6 @@
         print('if {$fullbox == ""} {', file=ofile)
         print('    set fullbox [box values]', file=ofile)
         print('}', file=ofile)
-        print('catch {set fullbox [property FIXED_BBOX]}', file=ofile)
         print('set xmax [lindex $fullbox 2]', file=ofile)
         print('set xmin [lindex $fullbox 0]', file=ofile)
         print('set fullwidth [expr {$xmax - $xmin}]', file=ofile)