AMAZING, thank you! That’s exactly what I needed!
Well, I’ve got a problem booting from a USB HDD where U-Boot recognizes it as a USB device, but not as a storage device, and skips it. If I run the command prompt and just do usb reset, that takes care of it - U-Boot then recognizes it as a storage device, and can boot from it. I posted some logs etc. to the forum, and then after playing around some more I posted an issue to GitHub, but to the wrong repo (this GitHub issue is more complete than the forum post).
Anyway, I suspect the problem is simply that the disk hasn’t spun up or something like that, so I plan on adding a boot delay, and, if needed, a usb reset to the USB boot command. I’ll try playing around now that I can save env to a FAT partition, thanks again!