Once you have upgraded to BIOS 70 or later, you cannot downgrade to BIOS 69 or earlier, so there is no way you can return to BIOS 52. What you need to do is add the configuration for your EDP display. Whatever instructions you used to do it the first time will be needed to do it this time. If a OEM provided this system to you, you need to contact them regarding this configuration.
Sorry,
...S
