Stuck at boot animation after 5.1.1 root attempt

I was messing around with rooting 5.1.1 and now I'm stuck at the boot animation, the word 'fire' in orange with yellow moving across it. I have adb and root; it's not totally bricked. I suspect that my mistake was, while haplessly pasting commands from the 5.0.1 root batch file, pasting the command "fastboot boot boot.img". I can issue reboot commands and it will reboot but still get stuck at the boot animation.

So, how can I get myself out of this mess? Do I need a 5.1.1 boot image from a volunteer?

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