"/hsave -u ..." is fine to also save items set with an expiration time. But it doesn't save the key-data pair with the actual unset value.
It would be nice to have another option to tell hsave to also save the current $hget().unset value.
And a similar one in hload to tell it to restore this value with or without compensating the time elapsed since the file was saved.
I've written 2 aliases to do exactly that. It works great but it's much slower than a native version.