How do I mount the OS (system) disk from the UEFI shell?

I have to run a firmware update script that lives on the first hard drive of an Intel server board. I must use the UEFI shell to run this script, according to the Intel docs.

(Our servers have no external USB ports, so please don't suggest this.)

I have all the binary firmware blobs including the update script in /moo on blk0.

How do I mount the drive so I can run the script or do I need to mount the drive at all?

We found a way to use Intel's sdptool using IPMI to the BMC. This is great because it obviates the need to mess with binaries on the host OS.

I have not documented the procedure yet but I hope to post something somewhere detailing all the steps. Honestly I don't understand the process well enough to explain yet. It's a lot of work and most of it was done by someone else on my team.