MobileRead Forums - View Single Post - Instructions for patching firmware 3.13.1

davidfor · 04-13-2015, 10:26 AM

The covers images don't come from the database. They are generated as needed from the books. For epubs, they are generated from the first page of the book. There are three or four different sizes generated for use in different places. And the sizes generated depend on the device. For books in the main memory, the generated cover images are stored for later use.

My guess is that something in the patch set the sizes of the images to be generated. These were saved and now that you have reverted the patch the stored images are being used. A test would be to send a new book to the device and see if the correct sizes are generated.

If I am right, the fix is to remove the stored cover images and restart the device. The latter is to clear the memory cache of covers so they will be reread or regenerated. The easiest way to delete the images is using calibre and my Kobo Utilities plugin. It has a function that will do this. It can also send covers from the library to replace the ones on the device. Alternatively, you can delete the books on the device and send them again.

04-13-2015, 10:26 AM	#33
davidfor Grand Sorcerer Posts: 24,905 Karma: 47303824 Join Date: Jul 2011 Location: Sydney, Australia Device: Kobo:Touch,Glo, AuraH2O, GloHD,AuraONE, ClaraHD, Libra H2O; tolinoepos	The covers images don't come from the database. They are generated as needed from the books. For epubs, they are generated from the first page of the book. There are three or four different sizes generated for use in different places. And the sizes generated depend on the device. For books in the main memory, the generated cover images are stored for later use. My guess is that something in the patch set the sizes of the images to be generated. These were saved and now that you have reverted the patch the stored images are being used. A test would be to send a new book to the device and see if the correct sizes are generated. If I am right, the fix is to remove the stored cover images and restart the device. The latter is to clear the memory cache of covers so they will be reread or regenerated. The easiest way to delete the images is using calibre and my Kobo Utilities plugin. It has a function that will do this. It can also send covers from the library to replace the ones on the device. Alternatively, you can delete the books on the device and send them again.