For educational purposes, I'm trying to install Crux 3.2 onto a ramdisk, naturally I know everything will disappear upon reboot, but I'm not worried about that - i'm just trying to see what can be done.

Going from the Official Crux 3.2 install guide, I go through all the same steps I generally follow, except to establish /mnt I do:

mount -t tmpfs -o size=8gb tmpfs /mnt

I can run the setup, I can setup-chroot, but I can't passwd

when I do passwd, it immediately tells me:

Changing password for root

Enter the new password (minimum of 5 characters)

Please use a combination of upper and lower case letters and numbers.

Bad password: too short.

Warning: weak password (enter it again to use it anyway)

passwd: password changed.

but I don't even have a chance to type anything, it just does all of that at once.

When I look in /etc/passwd  I can see a line for root, but no password, unsurprisingly.  

could the problem be in tmpfs?  I'm not sure what's really different here.

Thank you.