Kindle Cover Bug Fix Without Calibre?

[Silver Surfer]

Greetings Great & Mighty Ebook Device Wizards.
I have a Kindle Voyage that has the Kindle Cover Bug still (since it no longer receives updates from Amazon).
I also have an EOL Chromebook that I can no longer install/run Linux Calibre on.
Is there a way to manually fix the covers without Calibre?
I am only wanting to do this for future book sideloads so I am fine with fixing it one book at a time.
I have tried fooling around a little bit with editing ASIN numbers but nothing has worked so far.
Any ideas other than upgrading device/laptop?

Thanks,

SS

[shamanNS]

If you're writing about cover thumbnails displayed on Kindle's library section (and not about using book cover as screensaver) you could try using this Python script to automate "bulk" extract and create thumbnail images:

https://github.com/quiris11/ExtractCoverThumbs

[Silver Surfer]

Thank you, do I need Linux installed to run the Python script?*
Yes I am talking about the thumbnails.
The screensavers are working fine (even when there is no corresponding thumbnail).
Just in case there is anyone else on the planet as hopelessly obsolete as me:
I tinkered around a little bit more last night and I was able to fix the covers by inserting the thumbnail images into the system/thumbnail directory.
You just have to make sure that you copy the existing filename.
It was a little bit tricky figuring out which generic cover was linked to which book but a little trial and error solved that: is there a way to know from the filename of the thumbnail which book it belongs to?
I also discovered that the Kindle is particular about the image format. I'm not sure what the rules are for that (I just found one that worked and made sure that the others were close).
I can deal with this moving forward but it's pretty cumbersome so if anyone has any tips/tricks I'm all ears.

*I can't really run Linux on my Chromebook anymore since it is EOL. At least not as dual boot which is necessary for it to see the Kindle as a USB device.

[JSWolf]

Originally Posted by Silver Surfer

Thank you, do I need Linux installed to run the Python script?*
Yes I am talking about the thumbnails.
The screensavers are working fine (even when there is no corresponding thumbnail).
Just in case there is anyone else on the planet as hopelessly obsolete as me:
I tinkered around a little bit more last night and I was able to fix the covers by inserting the thumbnail images into the system/thumbnail directory.
You just have to make sure that you copy the existing filename.
It was a little bit tricky figuring out which generic cover was linked to which book but a little trial and error solved that: is there a way to know from the filename of the thumbnail which book it belongs to?
I also discovered that the Kindle is particular about the image format. I'm not sure what the rules are for that (I just found one that worked and made sure that the others were close).
I can deal with this moving forward but it's pretty cumbersome so if anyone has any tips/tricks I'm all ears.

*I can't really run Linux on my Chromebook anymore since it is EOL. At least not as dual boot which is necessary for it to see the Kindle as a USB device.

Forget this. It needs Python 2.7. Go with calibre once you get a new laptop to replace that chomebook.

[rupor]

Originally Posted by Silver Surfer

Greetings Great & Mighty Ebook Device Wizards.
I have a Kindle Voyage that has the Kindle Cover Bug still (since it no longer receives updates from Amazon).
I also have an EOL Chromebook that I can no longer install/run Linux Calibre on.
Is there a way to manually fix the covers without Calibre?
I am only wanting to do this for future book sideloads so I am fine with fixing it one book at a time.
I have tried fooling around a little bit with editing ASIN numbers but nothing has worked so far.
Any ideas other than upgrading device/laptop?

Thanks,

SS

I am not a wizard, but I think you can use https://github.com/rupor-github/fb2converter for that. Most of its functionality will be useless for you, bit "synccovers" subcommand will do exactly what you are looking for:

fb2c help synccovers

NAME:
   fb2converter synccovers - Extracts thumbnails from documents (Kindle only!)

USAGE:
   fb2converter synccovers [command options] SOURCE [DESTINATION]

OPTIONS:
   --width value   width of the resulting thumbnail (default: 330)
   --height value  height of the resulting thumbnail (default: 470)
   --stretch       do not preserve thumbnail aspect ratio when resizing (default: false)
   --help, -h      show help

SOURCE:
  full path to file/directory on mounted device
DESTINATION:
    always a path, output file name(s) and extension will be derived from other parameters
    if present - converter will not try to construct kindle thumbnails directory, will use destination instead

Synchronizes kindle thumbnails with books already in Kindle memory so Kindle home page looks better.

In should run on Windows from 7 up and does not require installation.

[BionicGecko]

Originally Posted by shamanNS

If you're writing about cover thumbnails displayed on Kindle's library section (and not about using book cover as screensaver) you could try using this Python script to automate "bulk" extract and create thumbnail images:

https://github.com/quiris11/ExtractCoverThumbs

This unfortunately only works on very old versions of the firmware (below 5.8.5); the final firmware update for the Voyage was 5.13.6, so if this particular device was regularly updated, the script won’t work.

[shamanNS]

@BionicGecko The script actually still does its job, as in it creates thumbnail files in /system/thumbnail with correct filenames.
Further behavior that is firmware version dependant and book format and cdetype flag (EBOK vs PDOC) dependant is the thing that determines if Kindle uses those files or not.
The thing that doesn't work on newer firmware (prior to 5.15.1 IIRC that fixed that issue?) is the combination of azw3 + PDOC flag = what you used to get when you send files via email or Send to Kindle, before Amazon started converting "personal documents" to KFX format (and probably you still get azw3 PDOCs on Kindle devices with firmware older than some arbitrary cutoff version).

Anything that goes through Amazon's conversion servers ends up with a file that has the cdetype flag set to value of "PDOC".

If you "sideload" your book using USB cable and make sure that book files have cdetype set to EBOK Kindle should use and display cover thumbnails... after you deal with that stupid overwritting of existing thumbnail images (= you would need to use the script 2 times with letting Kindle go online in between).

The only issue with that Python script that I can recall is that it had issues with filenames or title metadata?? when book title or author contained non-ASCI characters (= the script code doesn't support Unicode?).

I remember using modified version (modified to only "parse" KFX files + don't downsize the image + put the files inside a folder where ScreenSaver hack caches screensaver images; and repackaged into a KUAL extension so the script can be used directly on the Kindle itself) of that script to workaround a bug with ScreenSaver hack not extracting correct image from KFX books created by Calibre plugin + Kindle Previewer.
And I definitely used that on Kindle PW3 with firmware 5.9.7 which I've used for years and years before updating it to 5.13.6.