Changing registration status of a jail broken device requires that the "hotfix" or "MKK" package be reinstalled.
Changing registration status only effects our application keys, not the jail break key.
A PW-1 can not update to anything more recent than 5.6.1.1 and 5.6.1.1 can still be jail broken.
I assume your "5.6.2.1" is a typo.
An OTA update in the case of a PW-1 will not happen since there is nothing newer to update to. 
I certainly wish you people would learn to use our model specific nicknames.
It would save both you a lot of time and grief and us a lot of time and wasted effort.
A "Paperwhite Gen 6" (in the USA, it can differ depending on region of world) is a PW-2.
So:
1) You are using the wrong jail break thread - you should (well, must) use the current one for a PW-2
https://www.mobileread.com/forums/sh...d.php?t=275877
2) The current JB thread's first post was re-written a couple of days ago to include the OTA blocking directions near the top (in Step #0).
3) Use (or post) the first six characters of the device's serial number, and/or look them up in this table:
https://wiki.mobileread.com/wiki/Kindle_Serial_Numbers
And use the model specific nickname for your device.
Doing #3 will reduce the chance of you trying to follow the wrong directions and of people replying to your posts giving you the wrong answers.