Reinstall on a geli encrypted device

Hi there.

I am trying to clean install 13 on a drive, which contains a functional
geli-encrpyted zfsroot 12. I want the intaller (booted from a 13
memstick) to ignore what's on the drive.

What happens is, that booting from the memstick asks me for the geli
password for the drive.

If I give the correct password, the installer will hang at 'can't find
/boot/entropy'.

If I repeatly give the wrong password, the installer also will hang at
'can't find /boot/entropy'.

Pulling the drive, and dd'ing some starting sectors seems to be the only
'cure'.

Is there a way to tell the installation media (in my case memstick) to
not taste for whatever is there, but to ignore, and just leave me to
whatever footshooting I may be up to ?

MfG CoCo