2025-12-18 — I was browsing The Verge a few weeks ago, and came across a review for a peculiar little eReader. This tiny magnetic e-reader sticks to the back of your iPhoneAn e-reader that’s smaller than your phone.The VergeAndrew Liszewski Being someone always on the hunt for weird schemes to cut down on scrolling my phone all day, and being a big fan of eInk screens in general, I thought the stick-on-the-back-of-your-phone gimmick was a funny and clever idea, and I immediately ordered one from the manufa
I was browsing The Verge a few weeks ago, and came across a review for a peculiar little eReader.
The VergeAndrew Liszewski
Being someone always on the hunt for weird schemes to cut down on scrolling my phone all day, and being a big fan of eInk screens in general, I thought the stick-on-the-back-of-your-phone gimmick was a funny and clever idea, and I immediately ordered one from the manufacturer; It's only $69. Two weeks later it has arrived.
Does really it work in this manner? No. I am fairly certain anyone who has tried gave up immediately.
The built-in magnet doesn't seem to align with any specific phone model well, and I suppose it would also hinder wireless charging (something I don't use myself). I did buy a lot of accessories for it as well, such as stick-on magnet rings which would mitigate the alignment problem, but I probably won't use them. The added bulk of a phone case would also make the Franken-device difficult to hold, and I would be concerned that I would break the eInk screen if I ever dropped the combo.
Yes, I think it's great.
OK, with very specific caveats. If you are:
On the whole this is a very well-built device, especially given the price. It reminds me of my Remarkable 2 in density, material, and build quality. The screen and device overall has no flex and feels very solid.
The only negative I've noticed is, not being a touchscreen (which I think is a smart move), the buttons are a bit cheap and seem not to register sometimes, but not enough to be annoying. It's unclear if this is due to the hardware design, a response lag in the firmware, or both.
It's a bit surprising they squeezed WiFi functionality into this. It has Bluetooth, but I do not think at the moment there is any peripheral it practically supports. I suspect the ESP32 chipset they chose simply had both and they exposed it just to do it.
It's also notably more compact than the smallest Kobo currently on the market.
But are these specs enough to be a good eReader?
We'll get to the firmware overall in a bit and skip to the main question. For an average person is this a good eReader for .epubs?
No it's awful. It's possibly the worst eReader ever made.
I'm not an embedded hardware guy, nor an ebook format expert, so what follows is conjecture, but based on conversations I've read in forums and discussions from a guy working on a custom firmware for the device it seems like the 128 MB of RAM may be a bit misleading, or not the complete story. My best guess is that certain memory address ranges are allocated to specific tasks, and there is not a lot left over, specifically for full .epub support and fonts. I also wonder if the whole firmware is loaded into memory which contributes to the squeeze.
My (limited) understanding of .epubs is they are basically a container for HTML/XML files and a subset of CSS, so to faithfully render an ebook you're heading in the direction of a small web browser, which is a tall order on a device with minimal RAM and not much more than 100Mhz of CPU to work with. Fonts are a complex subject on their own, but generally the more fonts you can support at once the richer your rendering is going to be for specific formatting details such as italics, font weights, etc.
As a result of the above every .epub ebook looks atrocious, to me anyway. It seems like it does its best to produce a purely text output stripped of all other formatting, with only two font sizes natively supported. I've seen some conversations regarding side-loading perhaps better fonts, but I have not bothered to experiment with it. Books with various unsupported epub tags also just get passed through as-is as text and it looks ugly.
So why is it still compelling? What saves it from mediocrity?
The X4 seems to have saved itself almost by accident due to two related factors:
This binary format is essentially a series of bitmap images, either 1-bit (black and white) or 2-bit (4 color grayscale), one per page. With these two factors combined users realized you could ditch the comic use-case, and instead create a tool where you do the rendering of an .epub on a modern device, with whatever font, weight, margins, etc. you want, and export it to this bitmap image format already pre-rendered, bypassing the hardware limitations entirely.
Which they did.
At the moment there are only two major downsides to this approach:
However, the results are a night-and-day improvement.
Which you would prefer depends on your tolerance for page turn lag vs. text crispness. Admittedly the 1-bit doesn't look very good. I bumped the weight to 500 which helps. However it does have superior page turn responsiveness. The 2-bit has a, to me anyway, painful ~2 second lag which rapidly stacks if you're trying to dart back and forth between pages. I would not be surprised if this is a more achievable optimization target in the future than better .epub support.
I've personally found that playing with the font size and margins per book so you achieve about 18 lines per page is the most comfortable relative text size for me on the device. I also recommend choosing another font than the default, which has a habit of dropping characters. I get the best results with Noto Serif.
Overall I do not find this exporting step very onerous. It's not much more work than fiddling with a Calibre export which most people do for non-Amazon eReaders anyway.
Once I had several books converted to my liking the device really began to shine. It's incredibly portable, and perfectly fits into that niche of something you would reach for reflexively to pass the time in place of your phone.
Given the specs the default firmware is both limited and yet surprisingly feature rich. You navigate the main menu in a left to right Z direction, which is a bit clumsy.
The first is Read which picks you back up at the last book and page you've read. If you're using an .epub the book menu has the usual options, though a bit cumbersome to navigate like everything else.
The menu with XTC files is a lot more limited since all settings related to text functionality are stripped out due to not being applicable, and at the moment the Chapter functionality is still not implemented.
Next is Folder which is a very basic file navigator.
Settings has the usual options you would expect. Of note is "Power-off Screen," which when set to Custom lets you choose a supported image on your device as the splash screen.
Sync would probably be better called "network things" — this is where firmware updates and connectivity related settings are. Yes, it has over-the-air firmware updates with these specs, very cool.
The misleadingly named "Upload from PC" seems to actually be for safely ejecting the SD card and has nothing to do with networking. I assume this being its own setting probably prompts some kind of re-indexing afterwards in the background, because I would have just assumed you power it off first to remove the SD card.
At the moment "Upload from Phone" does nothing.
The curiously named "More Transfer Options" appears to start a web server which is a neat feature they've managed to include. I do not know why it is labeled "Other biographies." There are still some localization improvements to be done.
Connecting to the device and browsing to http://192.168.3.3 greets you with a basic configuration tool and file manager.
At the moment that's about it for the native firmware. Xteink is actively rolling out firmware updates, so I am interested to see where they'll go with it.
What elevated it to my new favorite device despite the limitations is it's essentially open hardware. It's one of the few devices I own where I can basically do whatever I want with it out of the box (that isn't a computer) for the foreseeable future, even if the company goes under or drops support. Within a month there was a new custom firmware being developed which is already usable and straightforward to install:
GitHubdaveallie
There is a site to assist with flashing your device with any given firmware:
A tool for porting your .epubs to XTC files:
A community-driven resource site:
readme.clubFlorent Bertiaux
A Discord:
DiscordA Subreddit with at this time 8,400 weekly visitors.
A companion Android app that provides wallpaper and more feature-rich file management:
GitHubmeta-boy
Best place at the moment is from the manufacturer:
XteinkXteink
At time of writing it takes about two weeks to arrive from China.
I did get the case as well. It seemed to have an alignment issue and doesn't sit quite right, so I don't use it, but this could just be a manufacturing inconsistency. Other people seem to like it, so your mileage may vary.
Happy Hacking.