[juliazero]

Sorry about that . I answered you in PM about how to recover these files. I did mistake again in script.

for otabin_bck in "$1" "$2"; do
      mv "$otabin_bck" "$otabin~"
done

"migrate_to_binaryrenamer" )
    migrate_from_renameotabin /usr/bin/otaupd.bck /usr/bin/otav3.bck

I rewritten it now to:

for otabin in "$1" "$2"; do
      mv "$otabin.bck" "$otabin~"
done

"migrate_to_binaryrenamer" )
    migrate_from_renameotabin /usr/bin/otaupd /usr/bin/otav3

This is the same behavior that is working for restore ota or block ota update buttons. I don't know why I changed behavior for migrate button, everything I should do is just copy function and add .bck after $otabin
....
This day is a mess for me

https://github.com/NiLuJe/KindleTool you can use this tool to extract update and set files back. If you don't know how I'll help. And I'm sorry for making trouble for you.

V2.1 reuploaded.