You can't do an overwrite without being the admin.
You can get the IP address simply by pushing the Machine status button which will give you the IP (IPv4 Address) in the middle of the screen
I'm assuming something has gone very wrong and that is why you are trying the overwrite, because the admin account locking it up sounds like something caused by whatever may have caused you to need to do the overwrite.
If that isn't the case, try updating the firmware from your Mac via the upgrade tool.
(You will still need the IP address and have to login)
We're trying to perform an on-demand overwrite on a printer. Following the instructions it asks to access the security settings. However, the security settings are not accessible from a guest login page. Instead, we tried to login, but after entering the username and password it gets stuck on a Please Wait screen for over 20 minutes while logging in.
We know we could also do this from the computer, but we need the IP address that we don't yet have access to. In order to get this off of the printer, it also seems like we need to login as it isn't initially displayed.
Any suggestions for logging into a printer when it gets stuck?? Or other ways to perform an ondemand system overwrite that doesn't require a login or IP address?