Hi all, came across this thread too late and erroneously tried to jailbreak my 5.8.10 PW3 via this guide:
https://www.ereader-palace.com/downg...n-2016-method/
I flashed update_PW3_5.7.4_initial.bin and it went through the downgrade process (took about 10 mins). Everything seemed to succeed, but now my device is in a bootloop:
https://i.imgur.com/IeKMj3c.jpg
Initially after the bootloop, my Kindle was still recognized when connected to USB, so I tried moving an empty DO_FACTORY_RESTORE file and rebooting. Now it is continuing to bootloop and my device is no longer recognized via USB.
Any chance of recovering from my mistake?