The upstream said "BYD only", he caught all the other head units: CarLink went from 51 to 161 stars in three days

CarLink is a free APK that you install on an Android car head unit. Plug in an iPhone for CarPlay, plug in an Android phone for Android Auto, and it detects the phone itself. It didn't invent any protocol. What it did was turn a viral BYD-only project into something that works on any car. After a Brazilian TikTok tutorial went up on Nov 2, it went from 51 to 161 stars in three days. This piece covers whose momentum it rode, who its users are, and what people building similar open-source projects can learn.

A Brazilian car owner's tutorial

On Nov 2, a Brazilian car account called @fepaixaocars (78k followers) posted a video titled "Como instalar Carplay ou Android Auto (com ou sem fio) em qualquer multimídia android, tablet ou celular", meaning "How to install CarPlay or Android Auto on any Android head unit, tablet or phone, wired or wireless." The description says "tested on Galaxy J5, Galaxy Tab A, Moto G7", and below it is a download link for CarLink v1.0.7 on GitHub.

The video didn't get big numbers: as of 11-06 it had 1,948 views, 40 likes and 18 comments (TikTok, 11-06). But the people watching were people who really wanted to install it. The next day Portuguese-speaking users started showing up in the issue tracker, and stars rose by 32 in one day. On Nov 4 they rose another 39, the biggest single-day gain to date.

(GitHub, daily records; 11-06 is the count on the GitHub page that day)

From Nov 3 to 5, the author shipped five versions in a row, v1.0.8 through v1.0.12. Together the five APKs were downloaded about 905 times (GitHub Releases download counts, 11-06). Earlier versions have been deleted, so how many people downloaded those is not visible.

Whose momentum it rode

2026 September: a big event hit the Android head-unit scene. You could run CarPlay with pure software, no hardware box needed.

• Sep 12: xcertplay launched (about 1,574 stars), proving Android head units could run CarPlay using the Apple authentication chip already inside the machine.
• Sep 24: DiPlay launched, reaching about 13.3k stars and 1,713 forks in a little over a month, and gaining 556 in the last 7 days (GitHub, 11-06). Its README is blunt: the APK ships an "experimental accessory identity recovered from the public Carlinkit firmware".

DiPlay's README also has this line: Only supports BYD DiLink head units; other brands are not supported and there are no plans to change that.

The problem is that many owners use off-brand Android head units (UIS8581, FYT, Allwinner T7 and similar chipsets), and some people use old tablets or old phones as car screens. The upstream turned these people away, and CarLink brought them in. The first line of its README reads: "CarPlay and Android Auto in one app, for any Android car stereo or tablet." That means one app with both CarPlay and Android Auto, installable on any Android head unit or tablet.

What it does

The protocol parts all come from the upstream. The author, Ayush Soni, is in Delhi, India. He has only this one repository on GitHub and 19 followers. He imported two BYD-specific projects from the same developer, DiPlay (CarPlay) and DiAuto (Android Auto), along with their commit history, merged them into one app, and turned the BYD-only features off by default so they only switch on when you select "BYD".

What he added himself is all in the experience layer:

• Auto-detection: plug in an iPhone and it uses CarPlay, plug in an Android phone and it uses Android Auto, with no selection needed. One iPhone and one Android phone in the same house can share a single app;
• The home screen has one status and one button: on first launch you tap "Allow all" and every permission is granted at once; low-spec head units can turn on a lite mode;
• One-tap diagnostic report: when the connection fails, the app generates a diagnostic and submits it straight to GitHub as an issue. Now over half the issue tracker is these automatic reports, so compatibility data for long-tail hardware is being collected for free;
• Not distributed through an app store: the README supports one-tap subscription via Obtainium, and the app checks GitHub Releases every 6 hours and asks the user before downloading a new version. In 3 days there were 5 versions, each with dozens to over three hundred downloads, which suggests people who installed it are following the updates.

The changes also come fast. On Nov 4, a user reported that the new version wouldn't open, and v1.0.9 that same day fixed it. The repository has a development guide written for Claude Code, so the author is clearly someone who writes code with AI (inference: the pace of five releases in a few days is probably tied to that).

Where users come from

It all happens in niche circles, with no money spent anywhere:

1. Reddit: the author posted "CarLink – New open-source app that runs both CarPlay + Android Auto on Android head units (auto-detects phone)" on r/Androidheadunits. Someone reposted it on r/HowToMen, and the post can also be found on the r/Carlinkitcarplay subreddit. The post date and engagement were not captured;
2. Brazilian TikTok: the tutorial from the opening. Afterward a Brazilian forked it into their own modified version;
3. Search traffic from the upstream: the Chinese DiPlay guide site diplay.org lists CarLink as a "universal dual-protocol version", with a GitHub link and a cloud-drive mirror (around 11-04). People who search "will DiPlay support my car" are sent there;
4. Head-unit forums: a user on the official DUDU head-unit forum posted CarLink screenshots and compared image quality with the original Carlink; someone on the Korean arca.live car board recommended its download page.

People in the issues come from Brazil, Indonesia, Turkey, Korea and India, on machines like UIS8581 head units, a Moto g20 used as a screen, a Huawei P20 Lite and a Leapmotor C10. These are people who won't pay $50–100 for a CarPlay box, or whose car didn't come with CarPlay.

Over 30 to 60 days, searches for "CarLink CarPlay" and "DiPlay" on X returned nothing, and there was no coverage from media, Hacker News or Product Hunt. Few people know about it.

Who it's competing with

Since 9, dozens of open-source implementations have appeared for "making Android head units run CarPlay". The only free, finished product I've found that covers "generic + CarPlay and Android Auto in one + auto-detection" is CarLink. But this spot isn't hard to take: if DiPlay drops the brand restriction, or another fork gets more stable, CarLink gets replaced. Others have already forked it: a Brazilian swapped in a different engine, and there's another mirror.

Two unsolved problems

Whether it keeps working. The whole line relies on accessory identity extracted from Carlinkit firmware. DiPlay itself says "no Apple certification" and "the private key in the APK can be extracted". Apple revoking the identity, issuing a DMCA, or a single iOS update could break this whole group of projects at once. Early CarLink versions were already pulled once by the author after "accidentally packaging signing material".

Whether it works once installed. The issues have many reports like "wireless won't connect", and the author has only tested it on one Redmi Pad. The real install success rate is unclear (inference: probably not high).

If it were you

C: you can learn from it, but copying it isn't worth much. Projects like this get stars by catching the exact moment the upstream goes viral, but the "make DiPlay generic" route is already crowded with dozens of projects, and CarLink itself has only 182 stars. Building another one, you'd get a small tail of this wave, and you'd share its legal risk.

Who it suits: Android developers with a pile of off-brand head units and tablets who can tune compatibility one device at a time, or people with communities in car-head-unit markets like Brazil, Indonesia or Turkey.

Who it doesn't suit: anyone who wants a project they can keep on their resume and that will still be alive in a few years. This line could be cut off by Apple at any time.

How to do it: what's worth learning is the playbook, not this particular project. First, target the people the flagship project explicitly turned away: the "won't fix" and "not planning to support" lines in the README are a ready-made gap, so build a finished package for them. Second, make the product dummy-proof: one button, auto-detection, all permissions granted in one pass. Upstream users and your users are different people. Third, let the issue tracker collect data for you: a one-click diagnostic report that files an issue directly. Fourth, use GitHub Releases as your app store, paired with Obtainium and in-app updates. If you still want to play this line, go after the part CarLink hasn't nailed: wireless connection stability, plus a compatibility table listing which head-unit setups work and which don't.

How to acquire users: go where the people the upstream project rejected gather, like r/Androidheadunits, Carlinkit-related forums, and head-unit forums in Brazil, Korea, and Indonesia. Get a local car YouTuber to film an install tutorial. Then get the upstream project's guide sites and directories to list you. Searches for "will my car work" will bring the traffic.

When to move: this wave rides on DiPlay, which is still growing. The window is probably another month or two (inference). Once the upstream opens up brand restrictions, this gap closes.

What would mean I read it wrong: (1) CarLink passes a thousand stars in a month or two without being absorbed upstream, which would mean a general-purpose integration build can hold its own and there's more room to follow than I'm estimating. (2) DiPlay announces support for all head units in its README and CarLink's growth stalls, which would mean these projects are just living off the upstream's time lag. (3) Apple revokes the signing identity or a DMCA takedown hits, and the whole line stops. The third case isn't a misread, but it means entering now is pointless.