Review: The Xteink X4 E-Ink Reader

By Max Glenister | Published June 23, 2026

I have spent the last few months experimenting with the Xteink X4, a diminutive e-ink device priced at just £40. It is designed to be small enough to attach directly to the rear of a smartphone. After seeing mentions of the device from enthusiasts like joelchrono, moddedbear, Neil Brown, and Khairul Selamat, I decided to pick one up.

🛠️ Hardware & First Impressions

Upon unboxing, the first thing I noticed was how incredibly lightweight the X4 is—so light that it practically disappears in a pocket.

Out-of-the-Box Experience

Display: Crisp and clear for its dimensions.
Storage: Includes a branded 16GB microSD card.
Accessories: Comes with a card reader and a metal adhesive ring for MagSafe.
MicroSD Slot: ~~Easy to use~~ $\rightarrow$ Actually quite awkward; I had to use a stylus to eject the card.

Mounting & Portability

While I use a MagSafe case on my Pixel 7a, the spot is already occupied by my wallet. Furthermore, I discovered a polarity quirk: the X4 mounts inverted on some third-party MagSafe cases. Ultimately, the device's true strength is its sheer portability rather than its mounting capabilities.

💻 The Software Ecosystem

The stock firmware is functional but bare-bones. It defaults to Chinese (though I managed to switch it to English quickly via blind navigation) and offers only three fonts and basic layout controls for EPUBs.

To truly unlock the hardware, you need custom firmware. Most of these are derived from CrossPoint.

The Firmware Tree

Installation Process

Flashing is straightforward, typically requiring a single terminal command:

# Example conceptual flashing command
xteink-flash --firmware crosspoint_v1.3.0.bin

Note: For those uncomfortable with the CLI, a web-based flasher is available. However, units sold via AliExpress often have USB flashing disabled, requiring the SD card flashing method instead.

Firmware Breakdown

Firmware	Primary Focus	Key Features
Papyrix	Pure Reading	$\text{Knuth-Plass}$ line breaking, TeX-quality justification, support for Arabic/Thai/Greek/Vietnamese.
Inx	Polished UI	Tabbed navigation (Library, Stats, Sync), per-book settings, OPDS, and a Corgi mascot.
MicroSlate	Writing	Bluetooth keyboard support, typewriter mode, auto-save, and WiFi sync.
TernOS	Retro/Dev	PalmOS-inspired; runs native Rust and classic Palm apps.
PlusPoint	Experimental	Adds support for JavaScript applications.

Papyrix is impressive for a budget device, supporting FictionBook, HTML, Markdown, and plain text, along with Calibre Wireless integration. However, I prefer Inx for its "app-like" feel and detailed reading statistics (tracking pages, chapters, and average time per page).

The "Oddities"

The community has created some truly strange software, including:

An MQTT-powered Tamagotchi that acts as a visual companion for an AI assistant.
A local browser-based tool to convert images into the specific $480 \times 800$ BMP format required for sleep screens.

🎨 Customization & Accessories

I didn't want the device rattling around, so I 3D printed a custom flip cover using my FlashForge AD5X (print time: ~1 hour). I integrated the included MagSafe ring into the case so the X4 stays securely seated.

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⚖️ X4 vs. The Heavyweights

Earlier this year, I reviewed the Bigme B6 (£125), an Android 14 color e-ink tablet. The comparison highlights a clear divide in philosophy:

"The X4 sidesteps the complexities of a full OS by being smaller and 'dumber' in the best way possible."

Feature	Bigme B6	Xteink X4
Screen	Color (Kaleido)	B&W
OS	Android 14 (Bloated)	Custom Lightweight
Performance	Stuttering animations	Instant paging
Portability	Tablet-sized	Pocket-sized
Complexity	High (Debloating needed)	Low (Flash and go)

While devices like the Kobo Clara Colour or InkBook Solaris Color offer a more polished entry into color e-ink, they still require a large pocket. The X4 simply disappears.

🏁 Final Verdict

For £40, the Xteink X4 is an absurdly good value—provided you are willing to move past the stock firmware. With Inx or CrossPoint installed, you get a crisp, instant-paging reader that you can actually carry everywhere.

Pros:

Extreme portability.
Vibrant community-driven software.
Inexpensive.

Cons:

~~Stock software is great~~ $\rightarrow$ Stock software is minimal.
Clunky microSD slot.
MagSafe polarity issues.