Libra 2 Libra 2 frozen, manual reset not doing anything

[Rkob]

Hi,

Last weekend, the following happened with my beloved Libra 2 (bought in June 2022):

• I was reading (with ~60% battery remaining) and made a highlight or a dictionary lookup (don't remember);
• The device froze for a couple a seconds;
• It then skipped to the beginning of the chapter I was reading and switched to the default publisher font (instead "Caecilia" which I was using);
• Tried to change back the font, but the dropdown didn't list all of them, only the Kobo* or Rakuten* ones;
• Exited the book and tried to open another one: got an error message saying that the format was not valid or the file corrupted (don't remember the exact wording);
• Tried to open the original book again: same error message;
• Put the device to sleep with the power button: the device looked asleep and displayed the book cover;
• Tried to wake it again: nothing happened.

It's now frozen and I cannot get it to start-up. 😕
I tried:

• Manual resets (both the "power button down for 30 seconds" and the "page-turn + power button down for 30 seconds" types) => Doesn't do anything;
• Connecting it to a charger => Doesn't do anything, the white LED does not light;
• Letting it charge for a couple of hours and then resetting it => Doesn't do anything;
• Connecting it to my PC: the disk got mounted once under a generic name, but looked empty. I tried again, and the disk does not seem to be detected at all. I may try on a Linux machine later to see if I get more information.

The warranty is long expired but I love this device and want to try to fix it. I would really appreciate some help/guidance from this forum!

Has any of you seen something similar before?
The erratic behavior before the complete freeze makes me think of a memory or file system corruption. Could a corrupted microSD card explain what I see?
Any idea about what I could try to investigate this further?


Regards,
--
Rkob

[Aleron Ives]

It sounds like your SD card may have died, so the OS no longer functions. You could purchase another SD card, ask for a Libra 2 system image in the image request thread, and then try to replace the SD card to see if that will bring it back to life.

[repilo]

After trying everything, you have nothing to lose by opening it up and replacing the micro SD card. I did it when my Libra 2 started freezing or even restarting on its own several times a day. It's not too complicated and is well explained in some posts. In my case, I cloned my own defective card (I assume the writing had started to fail but the original data was still intact), and it ended up as good as new.

[Apollyon202]

Seeing the increasing cases of dying Libra 2 devices probably because of the internal storage, I'll buy some microSD cards. What kind of storage would you recommend? Anything from a trusted brand between 32-128 GB, but it should be A2 class, right?

[Rkob]

Hi,

Thanks for your replies, Aleron Ives and repilo!

I managed to remove the original microSD card yesterday, following the instructions given by ilovekobo and Fritomaster in I changed the sdcard of my Kobo Libra 2.

I will try to flash and install a new card, and see if it revives my device.

Regards,
Rkob

[Rkob]

Originally Posted by Apollyon202

Seeing the increasing cases of dying Libra 2 devices probably because of the internal storage, I'll buy some microSD cards. What kind of storage would you recommend? Anything from a trusted brand between 32-128 GB, but it should be A2 class, right?

Good point, I hadn't thought of the Application Class.
But do we know what the Libra 2 HW supports? It seems that my original card was not that fast (SanDisk Edge, speed class 4).
I don't want to buy a fancy SD card and have it limited by the device HW.

Regards,
Rkob

[DNSB]

Originally Posted by Rkob

Good point, I hadn't thought of the Application Class.
But do we know what the Libra 2 HW supports? It seems that my original card was not that fast (SanDisk Edge, speed class 4).
I don't want to buy a fancy SD card and have it limited by the device HW.

Regards,
Rkob

For the most part, what is important to Kobo ereaders—like most Linux devices—is the small block read/write speeds.

In my testing, Samsung and SanDisk have pretty consistently had the best small block speeds. Some cards I tested were pretty pathetic when it came to small block speeds though they easily handled video streams.

[Rkob]

Thanks, everyone!
I can confirm that my issue was a dead microSD card: the device started once I replaced it.

Note that just pressing the power button after inserting the new microSD card did not start the device (I was disappointed, thinking something else was faulty). I had to connect the eReader to a charger and then press the power button.

But now I'm obsessing about the differences between my original data and the one contained in the new images.
I can easily change the serial number in the image, but is it really OK to run with different VCOM values and waveform tables?
One thing is having (hypothetically) slightly off grayscale images, but I don't want to harm my screen over time.

The waveform identifiers of my original Libra 2 (I had a photo of the firmware information settings!) and the different microSD card images are:

My Libra 2 (rev. E) | 400_B068_HH1D01_ED070KH3U3_VD1400-GOB_TC 
Image rev. A        | 400_B035_HH0701_ED070KH3U3_VD1400-GOB_TC2 
Image rev. B        | 400_B063_HH1901_ED070KH3U3_VD1400-GOB_TC6
Image rev. E        | 400_B036_HH2D01_ED070KH3U3_VD1400-GOB_TCB
Image rev. F        | 400_B102_HH3302_ED070KH3C3_VD1400-GOB_TC
Image rev. G        | 400_B069_HH2801_ED070KH3U3_VD1400-GOB_TC

Is there a way to know which of the images has the waveform tables that are "closest" to my display? (I could then create a new image with the "best" waveform partition and the rest of the data from the rev. E image.)
Is there any other way to obtain the waveform tables for my specific display without the data from my original microSD card?
What about the VCOM value, any way to find the one for my specific display and write it to the image?

Or is all that unnecessary, and I should just stop obsessing and read a book instead?

On a side note, I'm wondering how this works with the "replaceable" screens for the new Clara and the Libra Colour (see this and this). The only thing they say you have to adjust after replacement is the VCOM value.
Is the waveform data stored in non-volatile memory attached to the screen controller? Or do they only send screens of the same type/batch as the originals?

Regards,
Rkob

[Quoth]

Vcom is specific to an actual individual screen.
The waveforms are for a screen model.

[Waldy]

@Rkob
I'm not sure if I understood correctly.
You have saved the image of the original faulty Libra2 SD card (6E0) with the values 400_B068_HH1D01_ED070KH3U3_VD1400-GOB_TC.
You flashed this image to a new SD card, but the device does not work.
Then you flashed another Libra2 image (6E0) with the values 400_B036_HH2D01_ED070KH3U3_VD1400-GOB_TCB.
Now you want to get your original values back?
If it is as I described, then it is possible, depending on the state of your faulty image.

[Rkob]

I was probably unclear.
My eReader is starting properly with the rev. E image provided by DNSB. But I would like to run with waveform tables and a VCOM value as close to the original as possible.
Unfortunately I don't have an image of my Libra 2, and the original microSD card is completely dead (it was not detected at all on 3 different machines with different OSes).

1) Waveform
I happen to have a screenshot of the firmware information, which includes the waveform identifier (400_B068_HH1D01_ED070KH3U3_VD1400-GOB_TC).
I thought I could use this identifier to find which of the images (obtained from this forum) has the display –and thus the waveform partition– "closest" my Libra 2.
I can guess what some parts of the identifier mean but not others, which makes it difficult to choose.
But maybe it doesn't matter and I should just use the one included in the rev. E image?

2) VCOM
This may be easier: I managed to find the VCOM number of my display. It was not written on the display cable, but encoded in the QR code.
Does anyone know where it's usually stored in the microSD card image?
Or does the vcom.txt trick explained here (for newer Kobos) also works on the Libra 2?

Regards,
Rkob

[Quoth]

Waveform should be the same for same model of screen. It's screen technology specific, not each screen.

Vcom is for each screen, white/black & greys are wrong with wrong vcom.