Precision 7560 BIOS not showing dGPU

Hi All,

Dell engineers replaced the motherboard of my laptop twice. Ever since, I had intermittent issues when booting up. It does not always boot up. I have upgraded the BIOS.

I have noticed that when I disable Hybrid Graphics, it does not boot up at all. In the OS, I cannot see the discrete GPU listed at all, only the integrated Intel gGPU.

Also, the on the System Informatoin page on the BIOS, under dGPU Video Controller, nothing is listed:

I know that the laptop is shipped with 

490-BGQL : NVIDIA T1200 w/4 GB GDDR6

So I am wondering if the dGPU got disconnected during the motherboard replacement. Wouldn't the BIOS list the discrete GPU?

thanks