I’ve used Universal USB installer from pendrive linux to write the image (first link you posted)
I’ve used this and the other tool (multi boot) from pendrive linux for years.
I tried writing the image with Rufus, but I couldn’t see this menu at that time.
Since you suggested on my other topic that I should press a key to see it, i tried that again with Rufus
I could see the menu and I did a check disk which resulted in “No errors found”.
I opened the image in Virtual box too, which seems to dispay the same style of booting (with the boot menu hidden) as Rufus and the check disc for defects resulted in “No errors found” too.
So it looks to me that the image is fine and Universal USB installer may have a problem.
Since this tool is the only one that displays the text menu by default as opposed to Rufus and Virtualbox maybe the errors comes from there, as you suggested.
I will try to contact them, but I must tell you that I tried to contact them in the past a few times and never got any reply.
I’m not sure even if their contact form ever works.