[Solved] Dell Inspiron 5521 Insyde bios primary display adapter setting

Hello
I wish to unlock the primary display adapter setting in the Bios so that I can use the dedicated gpu for rendering AND display. My laptop has a muxless design, which means that the display is always drawn by the iGPU while the dGPU is only used for rendering in select applications. This causes a bottleneck on the dGPU which doesn't reach its full potential as a result.
My system:
Model: Dell Inspiron 15R 5521
CPU: Intel Core i5 3317u
GPU: Intel HD 4000 with AMD Radeon 8730m in Enduro configuration
Bios: Insyde H20 version A12, Link http://goo.gl/PlWDPq
Screenshots: https://db.tt/x6RoDElB & https://db.tt/6WC2mFAe

I tried using this guide to unlock the advanced settings (http://goo.gl/WPFfOL), but got lost when searching for the correct module, mainly because the bios used in the example is and HP one. My Bios is not RSA signed (checked with Andy's tool).

I can usually do this sort of thing myself, but this time I am stumped. If someone could point me in the right direction, or better still, unlock the primary display adapter setting for me, I would be really grateful.

Please let me know if you require any more information.