Bricked Kindle Fire HD 7 (2014) After Updating To 4.5.5

First, I flashed TWRP with Fire OS 4.5.3, (I downgraded from 5.0 with the 4.5.3 bin) then I installed a cm11 rom, and then flashed back to 4.5.3. I decided I didn't want to root it, so I decided to update via OTA, and when it finished installing the update, it simply restarted, and just shows an empty screen. (The screen isn't even on) The update was listed as Fire OS 4.5.5, and since it's in an OTA, I don't know why it (probably) bricked. Any help on this? (Or on WHY the update bricked my Kindle)

Thanks in Advance

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