Tried installing Junox 17.2 R1 on an NFX250 the other day, only to find out I couldn’t login to the JCP, and the documented default password didn’t work.
After much hacking around, booting the JCP in single-user mode, hand editing configs and checksums, etc. there is a new and simple way to login. From the JDM, run this command:
ssh jdm-sysuser@vjunos0
From there, you can edit the config, and set the JCP’s root password to whatever you want it to be.