Clara Kobo Clara won't boot

[Xenophon]

My Mom's Kobo Clara HD won't boot (or reboot). Sequence of events:

1. I had it connected to my Mac so I could use Calibre to load more book for her. It unmounted itself all on it's own, yielding a "disk not unmounted properly" warning from the Mac OS.
2. Screen flashed black-white-black-white.
3. No response to short presses on the power button.
4. Attempted a normal reset: Hold the power button until reboot begins. Saw the three dots that slowly refresh while the system boots.
5. Got to the end of that sequence, where you normally get the UI next. Instead, got a flash-to-white-screen.
6. Now, If I hold the power button for 20-30 seconds, I get the black-white-black-white flash, but nothing else. No reboot of any kind.

I can't update firmware, because I can't get the a point where it will mount as a USB drive. I can't seem to get back to the UI, no matter what I do.

Any suggestions for reviving the apparently-dead would be extremely welcome.

[DNSB]

I've sent you a link to a firmware image for the Clara HD. You will need to copy the image to a µSD card. You can either use a new µSD card or remove the µSD card from your Clara HD. I recommend the new card since often the problem with the device is the µSD card failing. The instructions are linked to in the PM.

[shyhermit]

DNSB,

Just a thought. There is a free utility called ImageUSB from Passmark (free license for personal use):

https://www.osforensics.com/tools/write-usb-images.html

It allows "whole image" to be flashed to USB based disks. Can it be used to recover Xenophon's Clara HD by simply finding a "stock" image of the Clara HD and "reflash" back to Xenophon's device to overwrite the presumably corruption partition(s)? Can such an image file be downloaded from Kobo or elsewhere for recovery purposes?

What about devices without microSD but instead built-in storage? Can this recovery method work?

[DNSB]

Originally Posted by shyhermit

DNSB,

Just a thought. There is a free utility called ImageUSB from Passmark (free license for personal use):

https://www.osforensics.com/tools/write-usb-images.html

It allows "whole image" to be flashed to USB based disks. Can it be used to recover Xenophon's Clara HD by simply finding a "stock" image of the Clara HD and "reflash" back to Xenophon's device to overwrite the presumably corruption partition(s)? Can such an image file be downloaded from Kobo or elsewhere for recovery purposes?

What about devices without microSD but instead built-in storage? Can this recovery method work?

No, it will not work. The exposed partition when you connect a Kobo ereader to your computer using USB is the only item you can see over that connection. For a Kobo ereader, you have no access to the two ext4 partition or the free space at the start and end of the disk. That is why you need to remove the µSD card from the ereader and mount it directly on your computer so the entire disk is accessible.

I looked at the ImageUSB utility at one point and it seemed to offer very little the the USB Image Creator and USB Image Writer utilities do not offer.

You may want to check the Use full 4GB in Newer Mini? thread for an example of why the µSD card must be removed to allow access to the full disk.

[shyhermit]

Ah.. That is too bad. Thanks for the warning, DNSB. In Windows, with a non-USB connection, such as SATA or IDE (old standard), it is possible to image a disk to include all partitions, regardless of the partitions' format.

Do you know of a way to "image" the entire Kobo eReader through an USB connection to include all partitions, including all "hidden" (usually inaccessible) partitions?

By your logic, if I use the ImageUSB utility, I basically am doing a backup of the exposed partition of my Kobo eReader? If this partition is ruined, can I at least use this backup to restore the partition to prevent Xenophon's situation?

Moreover, Pgaskin.net has links to all of the firmware .zip to current Kobo devices. Is it just the same to download one of those .zip for the said device (such as the Libra Colour in my case or Clara HD in Xenophon's case) and unzip to overwrite everything in the exposed partition to "reset" everything?

Originally Posted by DNSB

No, it will not work. The exposed partition when you connect a Kobo ereader to your computer using USB is the only item you can see over that connection. For a Kobo ereader, you have no access to the two ext4 partition or the free space at the start and end of the disk. That is why you need to remove the µSD card from the ereader and mount it directly on your computer so the entire disk is accessible.

I looked at the ImageUSB utility at one point and it seemed to offer very little the the USB Image Creator and USB Image Writer utilities do not offer.

You may want to check the Use full 4GB in Newer Mini? thread for an example of why the µSD card must be removed to allow access to the full disk.

[DNSB]

Originally Posted by shyhermit

Ah.. That is too bad. Thanks for the warning, DNSB. In Windows, with a non-USB connection, such as SATA or IDE (old standard), it is possible to image a disk to include all partitions, regardless of the partitions' format.

Do you know of a way to "image" the entire Kobo eReader through an USB connection to include all partitions, including all "hidden" (usually inaccessible) partitions?

If the entirety of the disk is exposed, no problem. The problem is that I am not aware of any ereader that exposes the entire disk over the USB connection.

Originally Posted by shyhermit

By your logic, if I use the ImageUSB utility, I basically am doing a backup of the exposed partition of my Kobo eReader? If this partition is ruined, can I at least use this backup to restore the partition to prevent Xenophon's situation?

Why bother? A simple copy of the contents of the exposed partition works as well as an image backup and makes access to the contents much easier.

Originally Posted by shyhermit

Moreover, Pgaskin.net has links to all of the firmware .zip to current Kobo devices. Is it just the same to download one of those .zip for the said device (such as the Libra Colour in my case or Clara HD in Xenophon's case) and unzip to overwrite everything in the exposed partition to "reset" everything?

Once again no. The overwhelming content of the firmware package is copied to the system partition on the Kobo during the install process. Very little if any is copied to the exposed partition. If you look at the files in the upgrade .zip file, the upgrade directory contains hardware specific updates and kernel updates, the KoboRoot.tgz is the rest of the upgrade. Looking at KoboRoot.tgz, I checked 7 firmware revisions and in none of them, did /mnt/onboard contain anything other than an empty .kobo directory.

If you remove the µSD card from a Kobo ereader and mount it on computer, you will find a chunk of "free space" where the serial number and boot related bits live, 2 ext4 partition (system and recovery), a FAT32 partition (the one that gets exposed over USB) and then some free space at the end of the disk which as far as I know is unused. BTW, the two ext4 Linux partitions are why many a poor fool has read and obeyed Windows request to format their µSD card.

I have played with doing a backup of the full disk in a Kobo ereader over a network connection but the problem is finding a way to restore that backup on a device that is not booting and had non-removable storage.

[Aleron Ives]

Do you have a set of working commands for killing Nickel et al., remounting the ext4 partitions as read-only, and imaging the SD card over Wi-Fi?

[DNSB]

A shell script cobbled together from various bits and pieces is a closer description. Uglier than homemade sin and I've only tested it on one device where it seemed to be working until the WiFi shut off.

There was an recent thread Can you create a micro SD card image without taking apart your Kobo? based on a script from 2015 that was run from KOReader.

Basically, kludge the shutdown processes from the KOReader script, unmount and remount the partitions as R/O and copy the data (latter two courtesy of geek1011).

[shyhermit]

Another excellent point, DNSB.

I suppose, for me, having a .bin/.img of the partition is much more comforting as a backup as it will be an one-step process to restore the partition. I always worry that a "simple" file copy will miss some files being copied that have strange filenames or fall under strange directory names which Windows or Mac does not recognize. This problem will not occur will a bitmap image copy. The downside obviously is the large file size.

BTW, I presume you have tried out Linux to see if you can force-mount the non-exposed partitions, in which case you can then image those partitions? I mean if Kobo's own update can access those partitions through USB, then there must be a way for those partitions to be accessed via other means.

Originally Posted by DNSB

Why bother? A simple copy of the contents of the exposed partition works as well as an image backup and makes access to the contents much easier.

[DNSB]

Originally Posted by shyhermit

BTW, I presume you have tried out Linux to see if you can force-mount the non-exposed partitions, in which case you can then image those partitions? I mean if Kobo's own update can access those partitions through USB, then there must be a way for those partitions to be accessed via other means.

The Kobo update does not access those partitions through USB. You copy the KoboRoot.tgz file into the .kobo directory and safely eject the Kobo. At that point, the Kobo's OS will see the update file and install it. That process runs in the Linux OS installed on the Kobo and with access to all the partitions.

To repeat myself, the Kobo ereader only exposes the FAT32 data partition over USB. It is not as if it connected the internal storage directly to the USB connection.

[shyhermit]

Thanks for the explanation, DNSB. I actually did not know this at all (more likely, I missed your previous explanation). This makes sense now. At least this means the user can't "screw up" the non-expose partitions. Me newbie learning time.

Originally Posted by DNSB

The Kobo update does not access those partitions through USB. You copy the KoboRoot.tgz file into the .kobo directory and safely eject the Kobo. At that point, the Kobo's OS will see the update file and install it. That process runs in the Linux OS installed on the Kobo and with access to all the partitions.

To repeat myself, the Kobo ereader only exposes the FAT32 data partition over USB. It is not as if it connected the internal storage directly to the USB connection.