DEC750 unable to boot via USB installer

[BondiBlueBalls]

Hello,

I received my new DEC750 yesterday, and decided to upgrade (nuke and pave) to a fresh install of 22.1 via USB installer. I used the instructions here (https://docs.opnsense.org/manual/install.html) to set up the USB drive on my Mac.

When looking for the new USB installer in the boot menu, it wasn't appearing. After setting the boot type to "Dual Type", I was able to attempt to boot under Legacy. That attempt would consistently fail and default back to the UEFI boot and internal SSD. I disabled "Automatic Failover" to force the USB install, and when booting again, the system would just hang.

I tested the USB installer on a couple other systems, including my production box (Protectli firewall running 22.1), and they booted to USB without issue.

What am I doing wrong? Thanks in advance for any assistance!

[BondiBlueBalls]

...and disregard. I was using the dvd image rather than the serial image. 

Thank you for reading, and sorry to waste your time.