MobileRead Forums - View Single Post - Libra 2 Libra 2 frozen, manual reset not doing anything

Rkob · 08-08-2025, 08:35 AM

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:

Code:

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

08-08-2025, 08:35 AM	#8
Rkob Reader Posts: 14 Karma: 10 Join Date: Jun 2022 Device: Kobo Libra 2	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: Code: 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