The OTA 4.1.1 & later 4.5.1 was pushed to Apollo & Saturn (NEW GEN HDX 8.9") Devices adding firefly functionality along with other functionality (WHICH ARE CRAP ACCORDING TO ME)
So in order to get the device back to JB ie.. 3.X version Contact amazon customer services and Say that the Kindle is not working properly after the updates & roll back to the 3.x version.
have the device fullly charged 80% or more and they will initiate a Rollback.
Remember the device will never Get any OTA after this !!
Also it would be a lot lot helpful if some one can locate the ota file downloaded (via ES file explorer) so that we can copy it & share on XDA & help other fellow men.
Also I'd request you to contact Amazon via Phone for Source Code & bootloader info & get the call escalated to higher officials so that there are possibilities of getting info.
I'd request all the devs & members to file a petition (Change.org) with regards to the bootloader and simultaneously work on development
All active members & Ashamed owners of HDX's (Ashamed because with marvellous hardware we have a Crappy OS) include or add devs in this sections via PM or replies so that they can look over this & find a solution soon.