Guide: XTEINK S4: the successor to X4 (mini Android eInk Reader)

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Great news! The XTEINK X4 is now available direct on Amazon.com
Next day delivery for Prime. Faster shipping than AliExpress!

If you’re on this page, you probably know all about XTEINK a company that makes small eInk devices that can, quite literally, attach to the back of your phone.

The most popular XTEINK device is the X4 (see the best guide for XTEINK X4 owners here; having issues with your X4, see my XTEINK X4 troubleshooting guide) and in February 2026, XTEINK started shipping the X3 (see my thoughts on the XTEINK X3 here). But! and this is the interesting bit, in April 2026 we’re getting an XTEINK S4… what is the S4? It’s the successor to the XTEINK S4.

In March/April 2026, XTEINK confirmed the S4 will be released and final design is locked. See the updated image on the right.. The S4 looks to be the best mini Android eInk Reader given XTEINK’s history with the X4.

Also coming out soon is the XTEINK X4 V2 Pro. It’s a non-Android, touchscreen X4 with a backlight. You can learn more about the XTEINK X4 V2 Pro here.

I’ll post more on the S4 and X4 v2 as it become available. For now, the only model directly available with US shipping is the X4 on Amazon.com

XTEINK S4 Specifications and Features

Here’s the (currently) known specifications and features of the XTEINK S4:

Android 11
2GB RAM / 32GB Storage
app support, including Kindle app!
backlight/frontlight (confirmed! see this video)
touchscreen
WiFI + Bluetooth
single front buttons
USB C charging (same as X4)
matte plastic, available in black and white
real time clock
MP3 Playback (it’s Android after all, but MP3 playback is verified)
4.3″ screen size (same as X4)
weight 100g (early prototype, subject to change)
thickness 6.9mm (early prototype, subject to change)
Price (China) is about USD$50. International Pricing not yet confirmed. See image to the right!

XTEINK moving from XTOS to Android 11 for the S4

This is news for those of us that run the X4 on Crosspoint. The S4 will run on Android 11 and support 32 bit apps. The good news, native Amazon support. The bad news, Android can be more taxing on memory requirements, and I worry the device may be sluggish. The possibly good news is XTEINK went with Android 11, this is an older version of Android and less taxing on memory – so it may all work out OK. The Boox Palma uses Android 11, and I haven’t heard complaints from people that own it.

XTEINK S4 Price and Release Date! Update: DELAYED!

China pre-orders were set to open April 27th, but XTEINK delayed this saying they would open orders at a later date. The China domestic price is USD$50. I am hoping they open international pre-orders around the same time. It looks like we’ll get a May release date.

XTEINK S4 v X4 Comparison

If you’re wondering how the S4 compares to the X4, there are some previews leaked on Chinese social media. See the image on the right, which shows the S4 is actually slightly more compact than the X4 but a fraction thicker.

There is a single front button which operates like a home button on older iPhones. There is a power button (top right).

The XTEINK S4 will 32Gb system memory (still not clear if this is a 32Gb microSD slot), it looks like it does on the top left side, using a tray type. It’s really hard to be 100% sure on this, as it could also be a button and reset pin hole. I’m really hoping it’s a microSD slot.

XTEINK S4 Software / Firmware

The current videos and screenshots are of Chinese firmware, and there’s some new features in the XTEINK S4. If you look at the leaked S4 image on this page, the main home screen options are (from top left, left to right):

Android 11
32bit Android App Support
Supported File Types: PDF/MOBI/EPUB/AZW3/TXT
Settings
File Manager
WiFi Book Transfer
Free Tomato Novels
WeChat Reading

No, Free Tomato Novels is not a mistranslation. Tomato Novels is a Chinese fiction site “番茄小说” (Fanqui Xiaoshuo), sort of Wattpad-like. It’s owned by ByteDance, yep, the company behind TikTok. So, this it will have store front integration, which is absent on the X4.

The store front integration is also confirmed by WeChat Reading which shows on the default screen. This is owned by Tencent and has a large library of licensed books, web novels, comics, and audiobooks. It integrates into WeChat, a ubiquitous Chinese everything app. There really isn’t an equivalent to WeChat in English-speaking markets.

XTEINK S4 Early Developer Preview

If you’re interested, here’s a video preview of an early development build of the XTEINK S4. This shows you how little has changed since the prototype to now and the clearest view of the OS. The text in the orange bubble confirms it’s the S4 preview. The main development board is connected via the ribbon cable, so this is very much a prototype and subject to change and the development board was obscured with the white lines in the original video.