Hi,
I did that upgrade on my Zenbook UM325U.
I replaced the ssd with a Samsung 980 Pro 1Tb.
It actually works fine, but for some reason the Bios seems to "forget" where it can find a bootable device seemingly at random.
This means that once every so many days it boots up in the BIOS and I have to create the Boot pointer there again. It is not a huge issue, but it is somewhat annoying. I have posted about this issue here on the forum.
cheers,
Hendrik-Jan