MobileRead Forums - View Single Post - Troubleshooting Covers not showing on home screen

shamanNS · 10-15-2015, 01:00 PM

Today I was experimenting with azw3 files and possibility of having non-generic cover after downloading book files via Dropbox. I was using my PW1 with fw 5.4.4. Just in case I've included plain old mobi files,for comparison.

First thing I've noticed that mobi and azw3 file don't behave the same, ie for mobi book any combination of CDE Type and (even deleting both 501 and 113 fields, not just value/content) field except "EBOK + ASIN has some value" (that one results in generic thumnail) results in PW1 extracting & creating thumbnail files which gets used. Basically you delete ASIN field you get a thumbnail, removing "personal" banner is totally optional. I've deleted thumbnail file from /system/thumbnails everytime I've copied new test version of same book. Also changed the title and ASIN value in cases were I was leaving ASIN field.

Not the same behavior for azw3, ie "has EBOK but ASIN field deleted" = generic cover. In combination (for example, after spliting dual mobi generated via KindleGen using KindleUnpack plugin for Calibre, and manually copy the azw3 file) where you get non-generic cover it's always small like this.

Now comes the crazy part. The same KF8 (split) file (and others tested on PW1 that showed cover thumbnail) when copied to my PW3 with fw 5.6.5 displays generic cover, while having thumbnail file present in /system/thumbnails/ folder ! (the file names is something like "thumbnail_random numbers" (since the azw3 file didn't have ASIN or CDE Type specified).

Sending az3 books (Calibre generated) via Calibre to that same PW3 cover thumbnails are there as they've always been, normal sized and are used. Although I did notice some "thumbinail_blablabla.partial (Windows Explorer shows them with Internet Explorer icon, like it was a webpage shortcut) files in /system/thumbnails/ folder after turning off Airplane Mode.

I was lazy to check I those partial files get created straight away after disconnecting USB cable, while in offline/ in Airplane mode, or the creation of those partial files is triggered by turning on the WiFi.

10-15-2015, 01:00 PM	#3
shamanNS Wizard Posts: 1,125 Karma: 12345678 Join Date: Feb 2010 Location: Serbia Device: Kindle PW5, Kobo Libra 2, Kindle PW1	Today I was experimenting with azw3 files and possibility of having non-generic cover after downloading book files via Dropbox. I was using my PW1 with fw 5.4.4. Just in case I've included plain old mobi files,for comparison. First thing I've noticed that mobi and azw3 file don't behave the same, ie for mobi book any combination of CDE Type and (even deleting both 501 and 113 fields, not just value/content) field except "EBOK + ASIN has some value" (that one results in generic thumnail) results in PW1 extracting & creating thumbnail files which gets used. Basically you delete ASIN field you get a thumbnail, removing "personal" banner is totally optional. I've deleted thumbnail file from /system/thumbnails everytime I've copied new test version of same book. Also changed the title and ASIN value in cases were I was leaving ASIN field. Not the same behavior for azw3, ie "has EBOK but ASIN field deleted" = generic cover. In combination (for example, after spliting dual mobi generated via KindleGen using KindleUnpack plugin for Calibre, and manually copy the azw3 file) where you get non-generic cover it's always small like this. Now comes the crazy part. The same KF8 (split) file (and others tested on PW1 that showed cover thumbnail) when copied to my PW3 with fw 5.6.5 displays generic cover, while having thumbnail file present in /system/thumbnails/ folder ! (the file names is something like "thumbnail_random numbers" (since the azw3 file didn't have ASIN or CDE Type specified). Sending az3 books (Calibre generated) via Calibre to that same PW3 cover thumbnails are there as they've always been, normal sized and are used. Although I did notice some "thumbinail_blablabla.partial (Windows Explorer shows them with Internet Explorer icon, like it was a webpage shortcut) files in /system/thumbnails/ folder after turning off Airplane Mode. I was lazy to check I those partial files get created straight away after disconnecting USB cable, while in offline/ in Airplane mode, or the creation of those partial files is triggered by turning on the WiFi. Last edited by shamanNS; 10-15-2015 at 01:02 PM.