The second that you register your Scribe, an update will automatically begin (rendering your device non-jailbreakable if your prior jailbreak did not succeed).
I recently completed the jailbreak for my Scribe (purchased from Amazon just 10 days ago - shipped with 5.16.2), following the directions found at
https://www.mobileread.com/forums/sh...&postcount=484 , with a couple of minor caveats:
1. I had to go to a shopping mall to find the requisite Wi-Fi gateway that required a web page;
2. After unsuccessfully trying to jailbreak 5.16.2 4x times (and factory restoring in between those times with the DO_FACTORY_RESTORE 0 byte file in the Scribe's root directory), I updated my Scribe to 5.16.2.0.1, and was able to jailbreak the first time I tried; and
3. In between steps 5 and 7 (in the link I reference above), I had to type ;uzb in the search bar (in demo mode) in order to successfully connect to my computer via USB to copy over (and install via UYK) both Marek's and NiLuJe's hotfixes (I may have used ;dsts command as well to access the 3-dot, upper right corner menu for UYK - not sure).
Other than those slight mods to the steps in link above, I followed the provided directions (thanks, mergen3107 and marzek), and was able to jailbreak my Kindle Scribe.
Now that I have KUAL installed, I have to figure out how to install KOReader to make it work (but that is for another thread).
Good luck!