Enable GRUB serial console

config/_common/grub-template.conf

@@ -1,24 +1,31 @@
 # GRUB 2 config file
+terminal_output console
+if serial --unit=0 --speed=115200; then
+    terminal_input --append serial_com0
+    terminal_output --append serial_com0
+fi
+
+set default="0"
 set timeout="5"
 set timeout_style="menu"
 
 if [ -s $prefix/grubenv ]; then
-    load_env
+    load_env --file $prefix/grubenv --skip-sig
+    set has_env="1"
+    if [ -n "${saved_entry}" ]; then
+        set default="${saved_entry}"
+    fi
+else
+    set has_env="0"
+    echo "WARN: failed to load env. Default choice will NOT be saved!"
 fi
-set default="${saved_entry}"
+
 
 function savedefault {
     saved_entry="${chosen}"
-    save_env saved_entry
+    save_env --file $prefix/grubenv saved_entry
 }
 
-if serial --port=0x3F8 --speed=115200;then
-    set has_serial=true
-    terminal_input --append serial
-    terminal_output --append serial
-else
-    clear
-fi
 
 insmod usb_keyboard
 insmod part_msdos
@@ -30,7 +37,5 @@ insmod gzio
 set gfxmode=auto
 insmod vbe
 insmod vga
-insmod gfxterm
-terminal_output console
 
 @@@MENU_ENTRIES@@@