Comment # 1 on bug 952955 from Marcus Schaefer

This goes down to a bad decision decision several years before. Actually the
name should have never been used as a path, which is the reason for the
problem.
The path '/' character is replaced by a '_' in order to create a shell variable
from it. That limits the name to contain '_' as part of the name

Actually there are limitations in what you can specify as a volume name in LVM
as an example too. Thus we are not free from limitations here depending on the
volume management system in use.

Unfortunately it would be a pretty big change in the kiwi boot code to
eliminate the use of a field separator. As long as it's just "ugly" to use a
mountpoint even though I think it makes the description more clear, I rather
would avoid to shift the priority on this.