Libra Kobo libra freezes (& reboots) after disconnecting from PC

SirBeardAlot · 04-25-2021, 02:43 AM

I've had my Kobo Libra H20 for a couple of months now, and it's been working just great up until now.

I've been side loading books with Calibre. But today something strange happened. I was uploading a handful of books then disconnected it from windows in the proper way.

The processing meter got stuck and nothing happened, after being frozen for a minute or so the Kobo restarted itself and seemed to work as normal, except for the new books not being added.

I can see the books on the device in explorer when connectedto my computer, but they don't seem to have been added to the database. I tried removing the books manually and readding them, but the same problem occured.

I also noticed that the Libra freezes as soon as i disconnect it from my PC and the back screen on it disappears, no matter if I add books or not. It stays frozen for a minute or so, then restarts itself.

I tried restoring an previous (working) database backup, but that did not fix anything whatsoever.

Any help I can get troubleshooting this will be much appreciated!

SirBeardAlot · 04-25-2021, 04:03 AM

A small update:
I removed the old database completely, restarted the Libra and it made a new database. All good so far.

Tried connecting it to the computer again and then disconnected it, only to have it freeze again as soon as it was disconnected from the PC. This makes me think that it is not a corrupted database, but something else.

SirBeardAlot · 04-25-2021, 06:08 AM

Update 2 (fixed):
I decided that i would remove all books from the device, to see if it was one of the books that was messing things up. I removed the books through calibre, but I was surprised to see that even though some books were supposed to be removed, they were still on the device. There were also empty directories (authors).

I removed these empty directories and the books that calibre did not detect through explorer.

Once the device was empty it would no longer hang once disconnected. I then started the process of re-adding books. Some at a time, disconnecting and letting the device update it's database every now and then.

At the moment the device is working as intended when disconnecting it from my PC. I'm still not sure which book (or whatever it was) that caused the problem. The only thing I've noticed that has changed is that the cover of the book I am reading at the moment no longer fills the screen completely when the Libra is in power save mode (despite no changes done to the cover).

compurandom · 04-25-2021, 07:53 AM

Quote:

Originally Posted by SirBeardAlot

Update 2 (fixed):
[...] but I was surprised to see that even though some books were supposed to be removed, they were still on the device.

These left over books were books that the device didn't fully process, and thus didn't put them in the database. This is why calibre didn't recognize them.

Most likely, these were corrupted books. It would have been interesting to make a list of those, and then see if they are in calibre, and if so, check if the file on the device is the same as what is in calibre.

There's a number of possibilities I can think of:

These books are also corrupt in calibre, in which case your problems will reoccur as soon as you transfer them
These books were corrupted during transfer but somehow didn't get noticed
These books were added to the device by some method other than calibre
These books were corrupted after being transferred, possibly by bit rot on the sd card or something, and the database was reset, forcing them to be re-imported
Somehow, the book was sent to the device from calibre more than once, but only one copy is corrupted.

If this happens again, it might be useful to check and see if there are books you sent to the device from calibre, but calibre doesn't show as being on the device, indicating it didn't scan correctly when importing books. Then, you'd have to hunt down where the corrupt file is on the device and manually delete it.

SirBeardAlot · 04-25-2021, 08:21 AM

Quote:

Originally Posted by compurandom

These left over books were books that the device didn't fully process, and thus didn't put them in the database. This is why calibre didn't recognize them.

Most likely, these were corrupted books. It would have been interesting to make a list of those, and then see if they are in calibre, and if so, check if the file on the device is the same as what is in calibre.

There's a number of possibilities I can think of:

These books are also corrupt in calibre, in which case your problems will reoccur as soon as you transfer them
These books were corrupted during transfer but somehow didn't get noticed
These books were added to the device by some method other than calibre
These books were corrupted after being transferred, possibly by bit rot on the sd card or something, and the database was reset, forcing them to be re-imported
Somehow, the book was sent to the device from calibre more than once, but only one copy is corrupted.

If this happens again, it might be useful to check and see if there are books you sent to the device from calibre, but calibre doesn't show as being on the device, indicating it didn't scan correctly when importing books. Then, you'd have to hunt down where the corrupt file is on the device and manually delete it.

Thank you for replying!
I think I've narrowed it down to two books that might have caused the problem. Though alot more were left half-processed (despite them working previous of adding the books that messes it all up).

In the process of re-adding books I only added a few at a time. The last time I only added two books and the problem came back. Only one book were actually added to the device though (visible in explorer). The second book did not get added at all. The half processed books above were probably a result of this same issue, it only added the first book but not the second.

I removed the book manually from explorer, hoping that would sort it out. But alas, it was not. I then tried to replace the database with the one that was working after i fixed it last time. But it still would not work!

All books were added with calibre, none of them are corrupt in calibre though. They have also been checked for errors. I am pretty sure the books that messed it up this time was among the last ones i added to the device before last time this happened.

I was hoping that I wouldnt have to re-do everything from scratch once again now that I've narrowed it down. But it seems that this cursed book is really messing things up, beyond just the database.

I've also noticed another very strange thing. Once this problem occurs, some of the covers of the books on the device gets the colors of their covers inverted (in calibre at least).

SirBeardAlot · 04-25-2021, 09:00 AM

I removed all books from Calibre once again, and ended up with empty directories and books that weren't removed. It seems that this corrupted book causes alot of damage, not to the actual database but to the filesystem or something.

Not sure if Calibre is causing this. Becuase the books were working before i added the "corrupted book". And i can use the same database once i remove the left over directories.

davidfor · 04-25-2021, 09:39 AM

Quote:

Originally Posted by SirBeardAlot

I removed all books from Calibre once again, and ended up with empty directories and books that weren't removed. It seems that this corrupted book causes alot of damage, not to the actual database but to the filesystem or something.

For Kobo devices, calibre works with the database on the device. This means that if a book is not imported by the device and added to the database, calibre does not know that it exists. It will not show it in the list of books on the device. If you send a book to the device, calibre will remember that it was send, but, if calibre looks for books again before you eject (such as after restarting calibre) it will not find these books.

When you delete a book from a Kobo device using calibre, it deletes the book from the database and the file system.

With the above, it means that if the device has not successfully imported the books into the database, calibre cannot remove it. If you look, the book files will be on the device.

Quote:

Not sure if Calibre is causing this. Becuase the books were working before i added the "corrupted book". And i can use the same database once i remove the left over directories.

When you eject a Kobo device, it looks for changes with books. It looks for any book that are on the device and not in the database. Or, have changed. It will then process these books and add them to the database. If importing one book fails, it will not import any further books. If you connect the device to the PC and eject, it will repeat the above. If the problem book is still there, it will probably fail the import again. And because of the order the device uses, it will probably be the first book tried and the failure will be immediate.

In most cases where there is a problem, the device keeps running. But, some books will not be there. In this case, the problem book is causing more problems. I suspect that when the book is imported, it is causing a process to hang, or appear to hang. The device has a process watcher (called sickel) that will reboot the device if it appears that any process has hung.

The only times I have seen this happen during the import is for a big book which also has a very big table of contents. And probably will only happen for kepubs. The import puts the ToC into the database. If that takes to long, sickel can see the process as hung and reboot the device. And this could result in a corrupt database as the reboot is done without guaranteeing any cleanup has been done.

SirBeardAlot · 04-25-2021, 11:09 AM

Quote:

Originally Posted by davidfor

For Kobo devices, calibre works with the database on the device. This means that if a book is not imported by the device and added to the database, calibre does not know that it exists. It will not show it in the list of books on the device. If you send a book to the device, calibre will remember that it was send, but, if calibre looks for books again before you eject (such as after restarting calibre) it will not find these books.

When you delete a book from a Kobo device using calibre, it deletes the book from the database and the file system.

With the above, it means that if the device has not successfully imported the books into the database, calibre cannot remove it. If you look, the book files will be on the device.

When you eject a Kobo device, it looks for changes with books. It looks for any book that are on the device and not in the database. Or, have changed. It will then process these books and add them to the database. If importing one book fails, it will not import any further books. If you connect the device to the PC and eject, it will repeat the above. If the problem book is still there, it will probably fail the import again. And because of the order the device uses, it will probably be the first book tried and the failure will be immediate.

In most cases where there is a problem, the device keeps running. But, some books will not be there. In this case, the problem book is causing more problems. I suspect that when the book is imported, it is causing a process to hang, or appear to hang. The device has a process watcher (called sickel) that will reboot the device if it appears that any process has hung.

The only times I have seen this happen during the import is for a big book which also has a very big table of contents. And probably will only happen for kepubs. The import puts the ToC into the database. If that takes to long, sickel can see the process as hung and reboot the device. And this could result in a corrupt database as the reboot is done without guaranteeing any cleanup has been done.

Thank you for taking time to explain this process for me. It is much appreciated.

The book that seemed to trigger this was about quite large, around 46MB if i recall correctly. It does not have a large ToC though, but alot of images. The one odd thing i can see is that it has a cover that is wider than its height. Not sure if that can cause anything like this though.

But maybe it is just the size of it, and that sickel reboots the device due to thinking that it has hung.

I still cannot understand how this can mess up other books though, that was not transfered at the same time and that was working prior to transfering the book that messed things up.

davidfor · 04-25-2021, 08:10 PM

Quote:

Originally Posted by SirBeardAlot

Thank you for taking time to explain this process for me. It is much appreciated.

The book that seemed to trigger this was about quite large, around 46MB if i recall correctly. It does not have a large ToC though, but alot of images. The one odd thing i can see is that it has a cover that is wider than its height. Not sure if that can cause anything like this though.

But maybe it is just the size of it, and that sickel reboots the device due to thinking that it has hung.

46MB is not that big if there are a lot of images. And if there ToC is not particularly big, it shouldn't have a problem. Any chance of seeing the book? If it is somewhere I can legally download it, can you post the link. Or, if it is in the public domain, you can post it here (not sure about the size though). Otherwise, you can upload it somewhere and send me a link. I'll try it on one of my devices and see what happens.

Quote:

I still cannot understand how this can mess up other books though, that was not transfered at the same time and that was working prior to transfering the book that messed things up.

Simple. Open a document on your PC, make some changes and pull the power cord out. Did the changes get save? Did the computer complain when it was started? That is basically what sickel is doing, restarting the device in a fairly brutal way that doesn't make sure changes are saved. And if it is in the middle of writing the changes to disk, you could lose a lot more.

SirBeardAlot · 04-26-2021, 01:47 AM

Quote:

Originally Posted by davidfor

46MB is not that big if there are a lot of images. And if there ToC is not particularly big, it shouldn't have a problem. Any chance of seeing the book? If it is somewhere I can legally download it, can you post the link. Or, if it is in the public domain, you can post it here (not sure about the size though). Otherwise, you can upload it somewhere and send me a link. I'll try it on one of my devices and see what happens.

Simple. Open a document on your PC, make some changes and pull the power cord out. Did the changes get save? Did the computer complain when it was started? That is basically what sickel is doing, restarting the device in a fairly brutal way that doesn't make sure changes are saved. And if it is in the middle of writing the changes to disk, you could lose a lot more.

Thanks again for explaining.

Unfortunately I cannot share the book in full without breaking any laws. And it's not really available for downloading or purchase anywhere for the public. It's a Daisy 2.02 book converted to Epub3 with Daisy Pipeline 2. The xhtml files are splitted at <h1> to avoid files > 260 kb. It has a total of 223 images between 50 and 500kb each, and a cover image that's 1650x1417 and it's size is 288 kb.

It also has an embedded font (Minion Pro), which I use for most books.

Is there anything I can do to troubleshoot it myself?

EpubCheck gives me the following:

EPUBCheck v4.2.4
Validating using EPUB version 3.2 rules.
No errors or warnings detected.
Messages: 0 fatals / 0 errors / 0 warnings / 0 infos

EPUBCheck completed

DNSB · 04-26-2021, 01:06 PM

You could try running the ScrambleEbook calibre plugin on the file and posting a link to the scrambled output. MobileRead limits epub/zip uploads to 20MB so you would have to use an external link (OneDrive, Google, DropBox, etc.).

JSWolf · 04-26-2021, 04:22 PM

Quote:

Originally Posted by SirBeardAlot

Thanks again for explaining.

Unfortunately I cannot share the book in full without breaking any laws. And it's not really available for downloading or purchase anywhere for the public. It's a Daisy 2.02 book converted to Epub3 with Daisy Pipeline 2. The xhtml files are splitted at <h1> to avoid files > 260 kb. It has a total of 223 images between 50 and 500kb each, and a cover image that's 1650x1417 and it's size is 288 kb.

It also has an embedded font (Minion Pro), which I use for most books.

Is there anything I can do to troubleshoot it myself?

EpubCheck gives me the following:

EPUBCheck v4.2.4
Validating using EPUB version 3.2 rules.
No errors or warnings detected.
Messages: 0 fatals / 0 errors / 0 warnings / 0 infos

EPUBCheck completed

One thing you can do to reduce the size is to remove Minion pro from the ePub. You do not need to embed it at all. You can side load Minion Pro to your Kobo and select to use that. No need to embed. Another thing you can do is load the ePub in the Calibre editor and do a lossless compress of the images to make them take less space with no loss of quality.

Then try the ePub again and see if your Kobo works with it.

SirBeardAlot · 04-27-2021, 12:59 AM

Quote:

Originally Posted by DNSB

You could try running the ScrambleEbook calibre plugin on the file and posting a link to the scrambled output. MobileRead limits epub/zip uploads to 20MB so you would have to use an external link (OneDrive, Google, DropBox, etc.).

That's a great idea. I hadn't seen that plugin before. The size of the book were reduced by like 90% though. So I guess it doesnt make "scrambled" images of the same size as the original book has? Thanks for the tip though! Will try it out.

Quote:

Originally Posted by JSWolf

One thing you can do to reduce the size is to remove Minion pro from the ePub. You do not need to embed it at all. You can side load Minion Pro to your Kobo and select to use that. No need to embed. Another thing you can do is load the ePub in the Calibre editor and do a lossless compress of the images to make them take less space with no loss of quality.

Then try the ePub again and see if your Kobo works with it.

You're correct. I do also got the font on my Kobo, so it's not really needed. But then again it's not really a problem considering size. I tried compressing the images but it made almost no difference whatsoever.

I found another book (similar in size and layout with many pictures) that are causing the same problem. Adding it and disconnecting the Libra from my PC made it freeze at 6% processing, and the problems started all over again. It copies the book in full to the Libra (i can see it in explorer, and also open it and read it from the Libra storage in calibre reader). But it wont get added to the database.

Other books work great with the same CSS etc.

Thankfully I've learned to take complete backups of everything on the Libra now, so I can just copy it all (books, database, settings etc) back without losing anyting.

DNSB · 04-27-2021, 11:40 AM

Quote:

Originally Posted by SirBeardAlot

That's a great idea. I hadn't seen that plugin before. The size of the book were reduced by like 90% though. So I guess it doesnt make "scrambled" images of the same size as the original book has? Thanks for the tip though! Will try it out.

The images are the same dimensions (i.e., a 1125x1500 image will be replaced with a 1125x1500 image) but the image content is generally a lot simpler and compresses better.

davidfor · 04-28-2021, 04:30 AM

@SirBeardAlot: I tried the three scrambled versions that you sent. Only one of them caused any problems on my test device. This was the whose title started with "Finna dolda ting".

Firstly, one thing that was mentioned, but I didn't explicitly ask, is what format are you using? I didn't have any problems with the books as epubs. It was when I changed to using the KoboTouchExtended driver that the problem arose. This transformed the books to kepub. And as I suspected early, triggered a problem with the ToC. But, not one I had seen before.

The three books are ePub 3. The have the ToC as both an NCX and NAV document. For ePub3, the device is using the NAV document to get the ToC.

When I looked at the NAV document, called "ncc.xhtml" in each book, there where three sections:

The basic ToC for chapters. This matched the NCX.
A page list.
The landmarks.

They were in that order and the landmarks were the largest section. As a test, I deleted the landmarks section, and the book was able to be processed by the device. I tried another version with the landmarks, but, without the page list and it didn't work.

Looking at the NAV document, the calibre editor showed it as 153.4KB. When I removed the landmarks, it dropped to 20.4KB. My assumption is that it was the sheer size of the text in the landmarks section that is causing the problem. There were only about 70 entries, so it had to be that. Or there was an error in them.

Beyond that, I can't say much. I know very little about how the NAV document works and even less about the landmarks. I have seen them before but not really looked at them. One thing that does look strange is that each landmark has "epub:type" of either "annotation" or "sidebar". My vague understanding is that they should point to sections in the book, such as the frontmatter, the backmatter and the first page of "real" content. As such, I would expect less entries and for them to be smaller. I don't know if this makes them invalid or not.

04-25-2021, 02:43 AM	#1
SirBeardAlot Member Posts: 17 Karma: 10 Join Date: Aug 2019 Device: Kobo Libra H20	Kobo libra freezes (& reboots) after disconnecting from PC I've had my Kobo Libra H20 for a couple of months now, and it's been working just great up until now. I've been side loading books with Calibre. But today something strange happened. I was uploading a handful of books then disconnected it from windows in the proper way. The processing meter got stuck and nothing happened, after being frozen for a minute or so the Kobo restarted itself and seemed to work as normal, except for the new books not being added. I can see the books on the device in explorer when connectedto my computer, but they don't seem to have been added to the database. I tried removing the books manually and readding them, but the same problem occured. I also noticed that the Libra freezes as soon as i disconnect it from my PC and the back screen on it disappears, no matter if I add books or not. It stays frozen for a minute or so, then restarts itself. I tried restoring an previous (working) database backup, but that did not fix anything whatsoever. Any help I can get troubleshooting this will be much appreciated!

04-28-2021, 04:30 AM	#15
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	@SirBeardAlot: I tried the three scrambled versions that you sent. Only one of them caused any problems on my test device. This was the whose title started with "Finna dolda ting". Firstly, one thing that was mentioned, but I didn't explicitly ask, is what format are you using? I didn't have any problems with the books as epubs. It was when I changed to using the KoboTouchExtended driver that the problem arose. This transformed the books to kepub. And as I suspected early, triggered a problem with the ToC. But, not one I had seen before. The three books are ePub 3. The have the ToC as both an NCX and NAV document. For ePub3, the device is using the NAV document to get the ToC. When I looked at the NAV document, called "ncc.xhtml" in each book, there where three sections: The basic ToC for chapters. This matched the NCX. A page list. The landmarks. They were in that order and the landmarks were the largest section. As a test, I deleted the landmarks section, and the book was able to be processed by the device. I tried another version with the landmarks, but, without the page list and it didn't work. Looking at the NAV document, the calibre editor showed it as 153.4KB. When I removed the landmarks, it dropped to 20.4KB. My assumption is that it was the sheer size of the text in the landmarks section that is causing the problem. There were only about 70 entries, so it had to be that. Or there was an error in them. Beyond that, I can't say much. I know very little about how the NAV document works and even less about the landmarks. I have seen them before but not really looked at them. One thing that does look strange is that each landmark has "epub:type" of either "annotation" or "sidebar". My vague understanding is that they should point to sections in the book, such as the frontmatter, the backmatter and the first page of "real" content. As such, I would expect less entries and for them to be smaller. I don't know if this makes them invalid or not.

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04-25-2021, 04:03 AM	#2
SirBeardAlot Member Posts: 17 Karma: 10 Join Date: Aug 2019 Device: Kobo Libra H20	A small update: I removed the old database completely, restarted the Libra and it made a new database. All good so far. Tried connecting it to the computer again and then disconnected it, only to have it freeze again as soon as it was disconnected from the PC. This makes me think that it is not a corrupted database, but something else.

04-25-2021, 06:08 AM	#3
SirBeardAlot Member Posts: 17 Karma: 10 Join Date: Aug 2019 Device: Kobo Libra H20	Update 2 (fixed): I decided that i would remove all books from the device, to see if it was one of the books that was messing things up. I removed the books through calibre, but I was surprised to see that even though some books were supposed to be removed, they were still on the device. There were also empty directories (authors). I removed these empty directories and the books that calibre did not detect through explorer. Once the device was empty it would no longer hang once disconnected. I then started the process of re-adding books. Some at a time, disconnecting and letting the device update it's database every now and then. At the moment the device is working as intended when disconnecting it from my PC. I'm still not sure which book (or whatever it was) that caused the problem. The only thing I've noticed that has changed is that the cover of the book I am reading at the moment no longer fills the screen completely when the Libra is in power save mode (despite no changes done to the cover).

04-25-2021, 09:00 AM	#6
SirBeardAlot Member Posts: 17 Karma: 10 Join Date: Aug 2019 Device: Kobo Libra H20	I removed all books from Calibre once again, and ended up with empty directories and books that weren't removed. It seems that this corrupted book causes alot of damage, not to the actual database but to the filesystem or something. Not sure if Calibre is causing this. Becuase the books were working before i added the "corrupted book". And i can use the same database once i remove the left over directories.

04-26-2021, 01:06 PM	#11
DNSB Bibliophagist Posts: 46,149 Karma: 168983734 Join Date: Jul 2010 Location: Vancouver Device: Kobo Sage, Libra Colour, Lenovo M8 FHD, Paperwhite 4, Tolino epos	You could try running the ScrambleEbook calibre plugin on the file and posting a link to the scrambled output. MobileRead limits epub/zip uploads to 20MB so you would have to use an external link (OneDrive, Google, DropBox, etc.).

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