Cant boot from pci expanded m.2

[Thedriveguy]

I have a dl380p Gen8 server that I wanted to boot truenas onto. I installed a pci expander for a m. 2 and installed it. I was able to install truenas on that m.2 but I was not able to boot from it. I didn't see anything like boot from pci in the boot order selector does anybody know what to do?

Thanks