[Help Request] HP Probook 4530s BIOS Downgrade from latest

[Rinceyster]

Hello,

since i am new to this Forum, i´d like to introduce myself and ask a question. If this post is considered offtopic here, please feel free to move it elsewhere.
I did a mistake and upgraded my Sandybridge HP to the latest BIOS 68SRR Ver. F.65. I´d like to downgrade this one to a Version where a Whitelist removal is possible. Maybe someone could give me a Hand and lead me step by step through the procedure to achieve my goal?

The reason is, i´d like to run an eGPU on this machine which is elsewhere usually stated as possible, but i run into a noboot when my rig is attached. without the eGPU powered on the machine boots normal.

I dont need help on the eGPU itself since this is pretty straightforward, all i need is someone who could help me to downgrade and antiwhitelist my bios then.

Any help is appreciated!

Cheers, 

Rinceyster