Unable to boot Windows 10 installer from an original usb thumb drive
Solution 1:
Ok, I make it boot after all and it turns out I did a mistake during selection of iso file to download.
While the bootloader on Windows 10 usb medium is a piece of crap, Windows 10 iso file provided by Microsoft should work - one just needs to pay attention to which version to download.
So for Windows 10 Home CZ FPP product we purchased, we should have downloaded Windows 10 edition. I was confused by missing description of each edition of iso file and the fact that our package sais czech edition which made me try Windows N edition allegedly targetted to EU market first. Sigh.