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davidfor · 03-07-2015, 05:56 AM

What Ripplinger suggested will help, but, it probably won't now. As the book is on the device already and covers have been generated, several things come into play.

The Kobo firmware generates covers for epubs from the first page of the book. So, if you open the book to the first page and see text, that is what is used. If it is a image, that will be used.

The cover is generated the first time it is needed. If the book is on the main memory it is saved to disk and reused. The KoboTouch driver handles this to a certain extent. If you resend the book, it will remove any generate and saved cover images.

If the book is on the SD card, it is not saved and will be generated each time it is needed needed.

The firmware keeps an in-memory cache of a few covers. This means it doesn't have to reread the cover image files that are shown on the home screen or being used for the sleep screen. And it means they don't have to be regenerated if the book is on the SD card.

You are probably being hit by the cache. If the cover is in the cache, there are two ways to remove it. One is to force it out by putting other covers in the cache. That means opening books, going through the library list and anything else that will do this. But, I don't know how big the cache is and hence don't know how many books you need to open or otherwise look at. The other way is to power off and on. This will restart the device and the cover cache (and any other caches that exist) will be restarted.

There is one other problem with the caches. If you delete a book from the device, the cover is not removed from the cache. That means if you use the device to delete the book, connect to the PC an send a new copy with a different cover, the old cover will still get displayed.

And as Ripplinger said, the driver has options to send the covers when sending the books. This is especially useful if you don't like the way that the device generates the cover. Also, you can use my Kobo Utilities plugin to remove or send new covers at other times.

03-07-2015, 05:56 AM	#5
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	What Ripplinger suggested will help, but, it probably won't now. As the book is on the device already and covers have been generated, several things come into play. The Kobo firmware generates covers for epubs from the first page of the book. So, if you open the book to the first page and see text, that is what is used. If it is a image, that will be used. The cover is generated the first time it is needed. If the book is on the main memory it is saved to disk and reused. The KoboTouch driver handles this to a certain extent. If you resend the book, it will remove any generate and saved cover images. If the book is on the SD card, it is not saved and will be generated each time it is needed needed. The firmware keeps an in-memory cache of a few covers. This means it doesn't have to reread the cover image files that are shown on the home screen or being used for the sleep screen. And it means they don't have to be regenerated if the book is on the SD card. You are probably being hit by the cache. If the cover is in the cache, there are two ways to remove it. One is to force it out by putting other covers in the cache. That means opening books, going through the library list and anything else that will do this. But, I don't know how big the cache is and hence don't know how many books you need to open or otherwise look at. The other way is to power off and on. This will restart the device and the cover cache (and any other caches that exist) will be restarted. There is one other problem with the caches. If you delete a book from the device, the cover is not removed from the cache. That means if you use the device to delete the book, connect to the PC an send a new copy with a different cover, the old cover will still get displayed. And as Ripplinger said, the driver has options to send the covers when sending the books. This is especially useful if you don't like the way that the device generates the cover. Also, you can use my Kobo Utilities plugin to remove or send new covers at other times.