configure GRUB to boot HOS automatically after 1s

Rsconscript

@@ -23,7 +23,10 @@ build do
           FileUtils.mkdir_p("#{tmpdir}/iso/boot/grub")
           File.open("#{tmpdir}/iso/boot/grub/grub.cfg", "wb") do |fh|
             fh.write(<<EOF)
+set default="0"
+set timeout=1
 menuentry "HOS" {
+  insmod multiboot2
   multiboot2 /hos.elf
 }
 EOF
@@ -66,11 +69,13 @@ EOF
           end
           File.open("#{tmpdir}/ext2/grub.cfg", "wb") do |fh|
             fh.write(<<EOF)
+set default="0"
+set timeout=1
 menuentry "HOS" {
   insmod part_gpt
-  insmod multiboot
+  insmod multiboot2
   set root=(hd0,gpt2)
-  multiboot /hos.elf
+  multiboot2 /hos.elf
 }
 EOF
           end