Alienware 17 r1 (2013) egpu

[Blauber70]

I have the following problem:

I want to use an egpu with my old alienware 17 r1. (using mPCIe) I build everything together but when I try to boot up I just get a black screen, I can't even open the BIOS. so I tryed to hotplug it but that didn't help either. Because a lot of other users used the Setup 1.35 I bought that. But even if I follow all steps, I still can´t boot while having the eGPU plugged in. Some said in other forums that you have to change the: "Bios-Primary display-IGFX or PCI" But I don´t find this option in my BIOS.

That's why I want to install a custom "unlocked" BIOS but I can´t find any for my particular model. Can I just use one which was made for the Alienware 17 r3?