@jdot @bidinou and anyone else experiencing this issue, you might like to know that I raised a warranty claim with Mudita support this morning.
My request:
*Dear Mudita Support Team,
I am writing regarding a persistent issue with my Mudita Kompakt, which was dispatched on 2nd May 2025 and remains within the 24-month warranty period.
The Issue
When using the Kompakt in direct sunlight, the e-ink display becomes washed out and difficult to read. Black (ink) artefacts on the screen fade leaving the impression that the screen is failing/has failed. It’s difficult to interact with the phone in this state. On a sunny day this can occur within one minute. (There is photographic evidence showing this on the link below.)*
The degradation occurs even on mild days — I have observed it at ambient temperatures as low as 16°C — and eventually resolves when I move the device indoors or into shade. Briefly pressing the power button to cycle the screen temporarily clears the degradation, though it returns upon further sun exposure.
I have tested this systematically. The issue is not related to any sideloaded app, occurs with and without a case, with and without a screen protector, and has been reported by other Mudita Kompakt users independently.*
This issue is outlined with photographic evidence on this topic on the Mudita forum. (This page)
Why This Is A Defect*
*Mudita’s product description states that the E Ink screen “remains clear and readable even in bright sunlight.” My experience is the opposite. The display becomes unreadable in precisely the conditions your marketing describes it as being designed for. I do not believe this reflects intentional behaviour, and I suspect it may indicate a panel tolerance issue — either in my specific unit or more broadly.
I should note that the degradation is fully temporary and reversible, so this is not screen burn-in. It is a response to solar exposure that signifies a manufacturing defect.
Action I Would Like
I would like to request a replacement device under the 24-month warranty. However, I am open to discussing whatever remedy Mudita considers most appropriate, including repair if you believe that would address the root cause.*
Mudita’s reply:
We have reviewed the forum thread you linked and are familiar with this temporary fading behavior. To help you understand what is happening, I want to provide some technical context about how the e-ink panel operates under specific conditions.
E-ink Panels and Thermal Strain
While e-ink is highly readable in sunlight, the physical microcapsules inside the display are sensitive to localized heat. Even on a mild 16°C day, direct solar radiation rapidly heats the dark ink particles under the glass.*
This physical behavior is often compounded by software. We have found that using third-party, sideloaded applications can directly cause this fading issue. Many standard Android apps are not optimized for e-ink and force the display controller to refresh at higher rates or use different voltage waveforms than our system intends. This throttles the e-ink screen to work in a different way, generating significant internal thermal strain on the hardware.
When the internal heat from the overworked display controller combines with the external heat from direct sunlight, it temporarily changes the viscosity of the e-ink fluid. This prevents the black particles from fully rising to the surface, resulting in the washed-out look you are seeing. Pressing the power button sends a full voltage clear to the screen, which resets the particles temporarily.
Next Steps for Warranty Evaluation
You mentioned that you tested this and believe it is not related to sideloaded apps. Because third-party background processes can alter the display driver and cause thermal strain even when you are not actively using those apps, we need to rule out software completely before replacing the hardware.
Please perform a full factory reset on your device and test it in direct sunlight using only the default MuditaOS, with absolutely zero third-party applications installed.
If the screen still washes out within a minute of sunlight exposure on a completely clean, factory-state operating system, then your specific unit likely has a manufacturing tolerance defect in the display panel. If the issue persists under these strict conditions, please reply to this email, and we will immediately initiate the warranty replacement process.
A couple of take-aways:
(1) Mudita are familiar with the issue
(2) Mudita insists that this issue doesn’t affect 1st party apps, only arising on 3rd party apps, which overwork the display driver and cause thermal strain when used in direct sunlight.
I will ponder this reply and see where it leaves me.
Step 1 is to get some data. I would like to test this claim that 1st party apps are not affected. In the first instance, I will test 1st party apps without factory-resetting the phone. (I’ll save that as a last resort.) In this effort, I wonder if I can call on the help of other users. @jdot, unless I’m mistaken you’re also in the UK where the forecast for the next week is typically overcast and cloudy, so the chances of testing soon are slim. @bidinou, are you in sunnier climes? If so, I’d be grateful if you could test 1st party apps and report back. (No need to factory-reset your phone on my account.)
Step 2 – testing after performing a factory reset.
Tune in for more on this saga later.
Merci.
@urszula
