https://www.mobileread.com/forums/sh...d.php?t=269099
It contains a lot of O.T. posts, but the full process is described as we (madmaxxx and I) worked it out.
Pay attention to the logs attached, they show what to expect (for a PW-3, but the PW-2 will be very similar).
If you want a main image other than the current one, go to the first post of the current jailbreak, step #7, open spoiler, there find a choice of 5 other firmware versions for the PW-2.
Don't be concerned about the diags system not working, you don't need it to recover the Kindle.