Why can't I restore Matshita UEFI DVD boot option on Latitude E6540 ?

Hello,

I'm stuck with this issue : I accidentally deleted Matshita UEFI DVD boot option on my Latitude E6540. I tried restoring bios to default with no success. I also tried to add a new boot option under UEFI boot manager, but still no DVD or CD option available. I finally upgraded from A11 to A12 bios verison. Still no luck.

I have Ubuntu installed, but still have free space and wanted to get Windows 7 installed (because I need to use Adobe Suite). But when I boot in Legacy (only available DVD boot option), I cannot install it because the partition is GPT.

There is the option of formatting my whole disk. But this is not an option. I just need to get Matshita UEFI DVD boot option back.

How can I make it out ?

Thank you and merry christmas