switch to grub2 eltorito from ancient syslinux v4,

update grub2,
predd 'd' in grub to show debug menu.

bootfiles/boot/grub/grub.cfg

@@ -1,3 +1,35 @@
+function toggle_entries {
+  if [ "${show_entries}" = "true" ]; then
+    set show_entries=false
+  else
+    set show_entries=true
+  fi
+}
+
+if [ x$feature_default_font_path = xy ]; then
+   font=unicode
+else
+   font=$prefix/font.pf2
+fi
+
+if loadfont $font; then
+  set gfxmode=800x600
+  set gfxpayload=keep
+  insmod efi_gop
+  insmod efi_uga
+  insmod video_bochs
+  insmod video_cirrus
+  insmod gfxterm
+#  insmod png
+  terminal_output gfxterm
+fi
+
+set show_entries=false
+set timeout=30
+set menu_color_normal=white/black
+set menu_color_highlight=black/light-gray
+hotkey d toggle_entries
+
 menuentry "Run __DISTRO__ with persistence" {
 	linux /vmlinuz perch
 	initrd /initrd.img
@@ -6,6 +38,7 @@ menuentry "Run __DISTRO__ from RAM without persistence" {
 	linux /vmlinuz toram
 	initrd /initrd.img
 }
+if [ "${show_entries}" = "true" ]; then
 menuentry "Run __DISTRO__ with debug" {
 	linux /vmlinuz debug
 	initrd /initrd.img
@@ -14,3 +47,17 @@ menuentry "Run __DISTRO__ with debug and first stage shell" {
 	linux /vmlinuz debug shell
 	initrd /initrd.img
 }
+fi
+grub_platform
+if [ "$grub_platform" = "efi" ]; then
+menuentry 'Boot from next volume' {
+	exit 1
+}
+menuentry 'UEFI Firmware Settings' {
+	fwsetup
+}
+else
+menuentry 'Test memory' {
+	linux16 /boot/memtest86+.bin
+}
+fi