Also w.r.t. multipath, disk-detect/multipath/enable is now enabled by default on Ubuntu on s390x, thus multipath installer codepath should be the one offered by the installer when the devices are scanned correctly. Moving this bug report to kernel package, as it seems to me this is a kernel issue and it's not the installer logic that is at fault.
Also w.r.t. multipath, disk-detect/ multipath/ enable is now enabled by default on Ubuntu on s390x, thus multipath installer codepath should be the one offered by the installer when the devices are scanned correctly. Moving this bug report to kernel package, as it seems to me this is a kernel issue and it's not the installer logic that is at fault.