diff --git a/hardware/Rakefile b/hardware/Rakefile
index 2784187..fac60c7 100644
--- a/hardware/Rakefile
+++ b/hardware/Rakefile
@@ -24,7 +24,7 @@ names.each do |name|
   # schematic revision, based on the number of schematic commits
   sch_rev = `git log --pretty=oneline "#{sch}" | wc -l`.chomp.to_i
   # pcb layout revision, based on the number of pcb commits
-  pcb_rev = pcbs.collect {|pcb| `git log --pretty=oneline "#{pcb}" | wc -l`.chomp.to_i}
+  pcb_rev = `git log --pretty=oneline "#{pcb}" | wc -l`.chomp.to_i
   # schema name with version and revition
   vsch = "#{name}_v#{version}.#{sch_rev.to_s.rjust(3,'0')}.sch"
   # pcb layout name with version and revition