diff --git a/mrbgems/full-core.gembox b/mrbgems/full-core.gembox
index 9a5b7081b..e0d008f06 100644
--- a/mrbgems/full-core.gembox
+++ b/mrbgems/full-core.gembox
@@ -1,9 +1,6 @@
 MRuby::GemBox.new do |conf|
-  conf.gem :core => "mruby-sprintf"
-  conf.gem :core => "mruby-print"
-
   Dir.glob("#{root}/mrbgems/mruby-*/mrbgem.rake") do |x|
     g = File.basename File.dirname x
-    conf.gem :core => g unless g =~ /^mruby-(print|sprintf|bin-debugger|test)$/
+    conf.gem :core => g unless g =~ /^mruby-(?:bin-debugger|test)$/
   end
 end