diff --git a/build_config.rb b/build_config.rb
index 39a1906..b343bcc 100644
--- a/build_config.rb
+++ b/build_config.rb
@@ -4,12 +4,9 @@ DEST_DIR = File.join(ROOT_DIR, 'dest').freeze
 MRuby::CrossBuild.new 'mrubyvisor' do |conf|
   conf.toolchain :gcc
 
-  conf.disable_presym
-
   conf.cc.defines   <<
     'MRB_NO_BOXING' <<
     'MRB_NO_FLOAT'  <<
-    'MRB_NO_PRESYM' <<
     'MRB_NO_STDIO'
 
   conf.cc.flags      <<
diff --git a/src/Makefile b/src/Makefile
index 6db2842..f966673 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -20,7 +20,6 @@ CPPFLAGS = \
 	-DKERNAUX_DEBUG \
 	-DMRB_NO_BOXING \
 	-DMRB_NO_FLOAT  \
-	-DMRB_NO_PRESYM \
 	-DMRB_NO_STDIO
 
 OBJS = start.S.o main.c.o
diff --git a/src/main.c b/src/main.c
index 4d72522..6ac5d8d 100644
--- a/src/main.c
+++ b/src/main.c
@@ -12,6 +12,7 @@
 
 #include <mruby.h>
 #include <mruby/compile.h>
+#include <mruby/presym.h>
 #include <mruby/proc.h>
 #include <mruby/string.h>