Hi,

when using debug on the kernel command line in order to understand a problem
inside iniramfs, cryptsetup does not prompt for a passphrase, it just hangs
forever.

Reading /usr/share/initramfs-tools/init it has a line
        exec >"$log_output" 2>&1
which redirects all output to /run/initramfs/initramfs.debug

It would be great to ensure that even with debug cryptsetup shows a prompt
and read a passphrase back from the console in the interactive case.

Maybe checking and ensuring stdin and stdout are a tty before calling
cryptsetup, or just call cryptsetup </dev/console >/dev/console

Bye,

Joerg