Clara HD Restoring backup to second device fails

[xembu]

Hi there!

I have 2 Kobo Clara HD devices. The first one is from 2020, the second is from 2021. I've made a full backup (image) of the SD card of the newer one, and I want to restore this to the older device. Unfortunately the restored image can't boot on the older device.

Please note that I'm aware of the various image request threads on this forum, but I'm not looking for an image, rather I'd like to understand what am I doing wrong/missing in my procedure of making an image.

The steps how I made my image:
1. Remove back cover of ClaraHD and unplug the SD card. (Right after unboxing, without ever starting the device, to have a pristine, stock image)
2. Insert SD card to reader and create image with dd command (macOS)
3. Replace SN in the image with old device's SN (using Hex Fiend)
4. Restore image with correct SN to old device's SD card.
5. Plug in SD card in old ClaraHD, turn it on and ... doesn't boot.

If I restore the old image to the old ClaraHD, everything works as it should, but does not with the newer image. Even tried with original image without changing SN, but still no luck. It feels like I'm missing an important step, like removing/cleaning some part of the new image to be able to restore it on other devices. Is there some "magic" that needs to be done, or my image is just somehow got corrupted? Can production date be a problem (newer image to older device)?

P.S: I currently don't have access to the new device (family member owns it and he lives abroad), which makes troubleshooting a little harder.

[davidfor]

That looks like it should work. It is basically what is being done with the images.

The things I would try are:

• A new card. I don't know why you are doing this, but, if there were problems before, it could be a failing card.
• Use the image without changing the serial number. It will be safe to reuse at least while you prove the process.
• Charge the device. Don't assume the charge level is what it was when you last used it.
• Do a manual factory reset according to the instructions on https://help.kobo.com/hc/en-us/artic...or-Kobo-Elipsa.

Other than that, what actually happens when you use the image? Does the power light come on? The screen change? The front-light do anything? The last suggestion above won't do anything if the device does not start at all, but, it can solve problems after an image is used.

[xembu]

Thanks for replying!

A new card. I don't know why you are doing this, but, if there were problems before, it could be a failing card.

Card shouldn't be a problem I think, because I'm using the same card for the old image as well, and with the old image everything works as it should.
The reason I'm doing is just to verify that the new image I've made is correct. I didn't create the old image (which works) myself, I've got it from here when my SD card went funny last year. We have bought a new one a few weeks ago and I taught it can be handy to have a pristine backup from a more recent device. And now I wanted to verify on my old device that the backup is working.

Use the image without changing the serial number. It will be safe to reuse at least while you prove the process.

I've already tried this, but no success.

Charge the device. Don't assume the charge level is what it was when you last used it.

I've tried this as well. But anyway it works well with the old image restored, so charging level can't be a problem either.

Do a manual factory reset according to the instructions on https://help.kobo.com/hc/en-us/artic...or-Kobo-Elipsa.

This doesn't work, tried to do it many times, but I think it already stops working before the factory reset procedure could kick in.

Other than that, what actually happens when you use the image? Does the power light come on? The screen change? The front-light do anything? The last suggestion above won't do anything if the device does not start at all, but, it can solve problems after an image is used.

The power light comes on for a few seconds (2-3sec), and then it goes off. The screen doesn't change at all, no front light either. If the USB is plugged in (PC <=> Clara), the power lights up for 2-3 sec, then pushing power button again and it lights up for 6 sec, pushing the power button long lights up for about 15sec and then again, nothing happens...


I've seen on the wiki (https://wiki.mobileread.com/wiki/Kobo_Firmware_Releases) that some devices can have different hardware versions. Can it be the case with the ClaraHD as well? Maybe the newer Clara is Mark8 instead of Mark7.