Burning ISO flash drive seems problematic?

[az2020]

Is your system UEFI? The 4.8 Release Announce is very clear on how to determine this.

Yes, I've had UEFI since 2014(?). Of course, the new machine (Ryzen 3) is.

I didn't realize LL was in the process of implementing support for that. (See previous post.). But, why would that cause a nested partition table? It seems to me like a legacy, non-EFI ISO image would still look like anything else.  I mean, if I had one in drawer from 2010, and plugged it in, it wouln't have a "nested partition error." I assume writing an old, non-EFI ISO today would produce a readable USB flash drive (not the partition error). Something still seems odd about that. But, it's a moot point if UEFI isn't supported yet.

Any prognosis about UEFI being official? I hope it's not to far off because I really like this distro.