Yeah, currently it is only meant to be used with non-expanded configs. Only RAM expansions are supported.
In theory it could "support" harddrives by ignoring UAE HD but it would only mean it would hang or crash when loaded program next attempts to access HD.
Or in worst case corrupt the HD if both original UAE config and config which runs ussload has same hardware HD controller. Obviously I won't allow this to happen, even accidentally.
Only UAE HD would be "safe" because it can't exist in real world
