Some have asked if the OTA blocker directory still worked on 8th generation devices running 5.8.5 -
Note: This status can vary for each and every firmware build.
It does, but not in the expected way.
The Kindle's system removes the directory entry, and creates a file with the OTA blocker name.
But in addition, you get a pop-up panel when an update is available and has been downloaded:
The message is (I paraphrase here):
"Not enough storage space to install the update."
When there is 2.4GB available.
The message should read:
"Mobileread user has OTA updates blocked."
After you acknowledge the notice, the system then deletes the *.partial file, leaving you without either the directory or filename.
So the next time it tries to download an update, it will succeed.
tl;dr:
If you ever get a popup panel telling you there is not enough space to install the update.
IMMEDIATELY go to 'airplane' mode after acknowledging the pop-up panel.
Then put your OTA blocker directory back and stay in airplane mode until we figure out how to deal with this new behavior.