Revert "[remaster] drop steambox install boot mode"

This reverts commit 2cfcfdb1aa.

remaster/standard_grub.cfg

@@ -81,6 +81,15 @@ menuentry "Media Center Installation" {
    initrd /boot/sabayon.igz
 }
 
+menuentry "SteamBox Installation" {
+   set gfxpayload=keep
+   echo "Language: ${bootlang}"
+   echo "Keyboard: ${bootkeymap}"
+   echo "Please wait..."
+   linux /boot/sabayon aufs cdroot splash quiet steaminstall vconsole.keymap=${bootkeymap} installer-gui locale=${bootlang} ${modeset_opt} ${acpi_opt} --
+   initrd /boot/sabayon.igz
+}
+
 submenu "Advanced Options" {
 
    menuentry "Console mode" {

remaster/standard_isolinux.cfg

@@ -13,6 +13,10 @@ label mceinstall
   menu label ^Installation (Media Center)
   kernel /boot/sabayon
   append initrd=/boot/sabayon.igz aufs cdroot splash vga=791 quiet installer-gui mceinstall --
+label steaminstall
+  menu label ^Installation (SteamBox)
+  kernel /boot/sabayon
+  append initrd=/boot/sabayon.igz aufs cdroot splash vga=791 quiet installer-gui steaminstall --
 
 label genuine
   menu label Safe ^Mode