[knc1]

I do not see: "login" anywhere on that screen.

So register it, if you can. That is the only sure way to find out if it is blacklisted.
In addition to the nagging notice, some features will be disable until it is registered.
or
Just ignore the nag notice
or
Search here for: fake registration, which you can also use as long as you are not trying to use a stolen device.

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If you are running firmware 5.1.2 or more recent, then try the "test" package in the current jailbreak thread. That will report if the jailbreak is present.

Or you can do as the directions say, just install again the bridge or hotfix package as described in the spoiler of the post you linked to.

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Please describe: "doesn't want to install"
We can not diagnose: "broke"

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You need to install something to enter text with, fastboot can not be used as a terminal.
What, if anything, have you already installed?
I can not see that you have installed KUAL yet, and that is pretty basic to using any of our add-ins.