Custom OS

This is a question about the X-series and N-series Dell switches.

http://www.dell.com/us/business/p/networking-x-series/pd

http://www.dell.com/us/business/p/networking-n1500-series/pd

1. What CPU's do these switches use?

2. Does the BIOS support booting from an external media?

I want to install a custom OS on my switches. I see that these series of switches have a console and usb port with firmware configuration support. According to CumulusNetworks this is supported with the S-series switches, but it's unclear what other Dell switches support this. Thanks!

cumulusnetworks.com/.../