Why I was thinking of MacOS resource fork files is that my Paperwhite does not have them so I doubt that they are from the Kindle OS.
I just tested with 5.16.9 by copying the update file from a MacOS virtual machines. After the update, the update_kindle_all_new_paperwhite_v2_5.16.9.bin update file was not present but ._update_kindle_all_new_paperwhite_v2_5.16.9.bin was present and it was the only file of that type that was present. So I will have to say that if you are manually copying the firmware update files to your Kindle from a MacOS computer, those resource fork files will be left behind.
|