Hello, Same problem here, this morning I did a fresh install on my Ultimo4k with stable release "openpli-8.1-release-vuultimo4k-20211128_usb.zip". Did not restore any settings, installed oscam from pli-feed, When I connect with telnet it ask for password for root, I have tryed without, my last I had before and so... nothing. I came from openvix 6.0.003, but did a fresh, but it doesn't work with the pwd I had on that image. So something is strange.. Maybee try older release?
Can't be, OpenPLi comes out of the box without password. Did you use ssh instead of telnet by any chance?
And yes, "setpassword" is a good solution if you want to set a password without using the commandline.
I use putty ssh port 22, and it was impossible to logon, after enter root at "login as:" it asked for "root@192.168.0.22's password:"