Inkpad 840 screen not updating content

[Silent Bob]

Hi all,
after using my Inkpad 1 for 4 and a half years without any issues, its screen is having serious problems.
As you can see in this video, the touch actions function but the screen updates its content only if i first put the device to sleep and i wake it up.
https://youtu.be/8Fv6f-Dx9nk

Earlier today, i have managed to upgrade to firmware 5.20 and then downgrade again to 4.40, in an attempt to see if can be a software problem.

Has anyone faced similar problems?
Do you think there is something that can be done, or should i start looking for a new device?
Would it be worthwhile trying to change the screen?

Update: After i posted, i saw that the screen doesn't refresh at all. I can turn the device on and of, i can tell it because the frontlight is getting activated and deactivated, but the screen is stuck to the recent events view.

[Silent Bob]

Today y removed the cover of the device and while i had it removed, the screen was working perfectly. It seems like there is a contact problem, most probably with the flex cable. I started to press it in various points to see where the problem was, and now the screen is forzen again, even with the cover removed.

Another thing that struck me is that i found a handwritten tag inside the device and something written on the motherboard, as you can see in the attached photos. I bought the device new and sealed, could it have been refurbished?

[rkomar]

I have a similar note stuck inside mine, and I don't think it was a refurb unit. The writing looks like some kind of measured values that might be used to tune the system.

[Silent Bob]

Originally Posted by rkomar

I have a similar note stuck inside mine, and I don't think it was a refurb unit. The writing looks like some kind of measured values that might be used to tune the system.

Very interesting. I was thinking of buying Inkpad 3 from the same store and seeing that tag made me doubt about their honesty. Thanks for the info rkomar.