The brilliant Luigi Auriemma wrote and made freely available a small tool called uif2iso which is a small utility that, as it implies, converts a uif file to a usable iso image.
Start by downloading the zip file from the link above and extracting the archive to a convenient place. Using Ubuntu, you'll need some dependencies as the readme states (uif2iso.txt):
$ sudo apt-get install zlib1g zlib1g-dev libssl-dev
Now, move to the src directory and make the executable:
A few blips later and the binary is created. You can either execute the binary directly, or type make install to install it to /usr/local/bin/ so it can be referenced anywhere.
To convert the uif:
$ uif2iso "my file.uif" shiny-new.iso
And as the author notes:
I don't like and don't approve the UIF format because it's proprietary
and doesn't give benefits.
What you can do with UIF can be done better with ZIP or 7zip without
the need to be forced to buy a software like MagicISO only for burning
Ok exists my tool which can do the job but this is not a valid reason
to continue to use this useless format.
So if you want to create a CD/DVD image, DO NOT USE UIF!