UEFI USB boot fail to a WYSE 3040

I have 2 problems, related to 2 separate installs, so first, here's #1:

Trying to install Allstarlink on a WYSE 3040; it's bundled with a lite version of Buster. Using a factory reset unit, and all the proper settings for UEFI USB boot set, I can't get it to even recognize the USB stick. Whether expanded out onto the media or just the .iso written to a freshly formatted FAT32 filesystem, same story. However, both the Debian 11 .iso w/its filesystem expanded out or the Clonezilla Live image will be recognized and boot correctly (same media). The closest case I've found was a discussion about alternate EFI files; something about fallback. I'm stumped; please help.