Reverse engineering paper #1 — the export Sealion 7 has no navigation engine · BYD Lab

Every assumption anyone makes about writing software for a Sealion 7 depends on this one fact, and it is not the fact most people assume.

Question#

Does an export-market Sealion 7 head unit run BYD’s own navigation engine — the one the domestic cars ship — or does it not have one at all?

Environment#

Decompiled read-only with jadx 1.5.5 from APKs pulled off the unit: BydSpotifyMusic.apk, CarAdapterService.apk, ClusterCommService.apk and ts-ncm-service.apk. Probed on the car over adb with pm, dumpsys and getprop. The unit identifies as ro.product.model = BYD AUTO, ro.product.device = DX_BYD_AUTO, ro.hardware = qcom — a Qualcomm SA8155-class platform running Android 11, with a ThunderSoft (“ts”) software layer on top.

Observation#

There is no turn-by-turn application on the car. A package listing and a launcher-activity query return no Neusoft, no OneCore and no Telenav map activity. The only launcher entry with a map-ish name is com.telenav.scoutivi.spotify.byd, and reading it shows it is a Spotify client with car controls attached — its Application class is BYDApplication, it bundles BYD’s vehicle SDK, and it draws no map.

What is installed is a complete projection stack: com.ts.androidauto.app with com.ts.androidauto.projectionservice for Android Auto, and com.ts.carplay.app / com.ts.carplay for CarPlay.

Evidence#

For contrast, here is what the domestic stack looks like. This part is the surviving record of an earlier decompile of BydMapLauncher.apk (v9.26.16.2b-G_NEU); that APK is not installed on this export unit and was not re-obtained, so it is reported as previously found rather than re-verified.

EvidenceProbableDecompiled code7 Aug 2026

MethodRecord of an earlier jadx decompile of BydMapLauncher.apk; not re-obtained on this unit

Domestic BYD navigation is com.neusoft.na.navigation — a thin Java UI over a native Neusoft “OneCore” engine (libna_onecore.so), sharedUserId=android.uid.navi, platform-signed. Position and heading are computed natively, not from Android Location: a Byd8155fPositioning class pushes raw NMEA, IMU and gear-signed vehicle speed into the engine over JNI at about 10 Hz, and the native pipeline runs Kalman fusion, then dead reckoning, then map matching, before rotating the map. The engine also requires an NDS world map database on the unit; without it there is no map and no positioning UI, which is the root cause of the “no navigation” complaint on domestic cars sold into markets whose map data was never shipped.

Interpretation#

Two different navigation stacks carry the BYD badge, and they have almost nothing in common.

The domestic one is a full on-board engine: it owns the position filter, the dead reckoning, the map matching and the car marker. Everything hard about vehicle positioning happens inside a native library on the head unit.

The export one is not a smaller version of that. It is the absence of that. On this car the head unit is a display, an input surface and a provider of vehicle signals — and every piece of navigation logic runs on a phone, in Google Maps or Apple Maps, behind a projection link.

Result#

Confirmed: the export Sealion 7 head unit has no on-board navigation engine. Navigation is delivered entirely by phone projection. Map matching, smoothing, dead reckoning, U-turn handling and divided-road logic all happen in the phone application; none of it exists on the car.

Three consequences follow for anyone writing software for this unit, and they are the reason the rest of this series exists:

An app that wants to navigate on this car is the navigation app. Nothing on the unit will map-match a position for it, and there is no engine to ask.
The unit is still a rich source of vehicle signals, and those are worth having — paper #2 is the catalogue.
The instrument cluster is reachable, but not through anything a domestic BYD app would use — the export unit routes through a different service entirely (paper #7).

Limitations#

One car, one market (Morocco), one head-unit build. Other export markets have not been checked and may ship a different package set; an EU or GCC car could plausibly carry a navigation app this one does not. Nothing here says anything about domestic Chinese units beyond the labelled record above, which was not re-verified.

The domestic-stack description is a second-hand record of our own earlier work, not a fresh decompile. Its native parameter names and thresholds are reported as previously found.

Reproduction#

On a car with adb reachable (our guide covers getting there):

Shell

adb shell pm list packages | grep -iE 'neusoft|onecore|navi|map|telenav'
adb shell cmd package query-activities -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
adb shell getprop ro.product.device
adb shell getprop ro.build.fingerprint

The first command should return no navigation engine. The second lists everything the launcher can start — read it in full rather than grepping, because the interesting result here is an absence, and an absence does not match a pattern.

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