Ok, so the list of easy to install utilities for 64-bit uefi seems never ending so I'll stop with Clonezilla.
Like some of the others, all it takes to boot on 64-bit uefi is to use the ZIP file. Unzip it to a fat32 drive. Done. Well, eject/unmount nicely.
The docs show how to do this, but like some others, state that you must use the special exe or sh file to make it bootable after you have unarchived it.
On modern machines, this is not necessary.
BUT, some of the projects are taking their docs from a FOURTEEN year old (coming up on 15 years) doc from the PenDriveLinux project.
Hardware has moved on since 2007, and fortunately it is now just a simple unarchive and copy method of install.
Only Porteus explained it - the exe and sh files are for bios machines, but for modern machines (say post 2007 when the pendrivelinux docs came out), the need for the exe or sh file is not really necessary.
Just sayin' - the casual reader of those projects may gaze upon what looks like a huge multistep procedure, when the reality is modern gear has made it oh so easy.
Ok, I'll be good, there are many others that follow this simplified procedure (but they probably point to the 2007 docs). That's ok, I'm good removing an unnecessary step.