How to show letters at cryptsetup luks preboot password entry prompt as typing?

At the moment cryptsetup luks preboot password entry prompt shows not even asterisk symbols while typing. Password entry is functional though. But this is too difficult for some users. How to make cryptsetup luks preboot password entry prompt at least show asterisk while typing? Is it possible to make cryptsetup luks preboot password entry prompt show the real password letters as it is being entered? (Similar to web forms "show password" boxes.)