diff --git a/docs/android.md b/docs/android.md
index e8efcf4b23..99a0f2ee62 100644
--- a/docs/android.md
+++ b/docs/android.md
@@ -13,6 +13,18 @@ EAS profiles: `development`, `production`, and `production-apk` in `packages/app
 
 `development` uses Android `debug`.
 
+## Version codes
+
+`packages/app/app.config.js` derives Android `versionCode` from the package version with:
+
+```text
+1_000_000 + major * 1_000_000 + minor * 1_000 + patch
+```
+
+Prerelease metadata is ignored, so `0.1.102-beta.1` and `0.1.102` both produce `1001102`. The same value is used as the iOS `buildNumber` because `packages/app/eas.json` uses EAS's local app version source. The `1_000_000` floor keeps the local formula above prior EAS remote counters during the transition. Do not re-enable EAS remote version counters or Android `autoIncrement`; F-Droid and other source-based builders need the native build number to be visible in the repo.
+
+The formula reserves three digits each for minor and patch. If either reaches `1000`, change the formula before cutting that release.
+
 ## Local build + install
 
 From repo root:
@@ -38,6 +50,19 @@ npx cross-env APP_VARIANT=production expo run:android --variant=release
 rm -rf android
 ```
 
+## F-Droid / source-only Android builds
+
+F-Droid builds should set `PASEO_FDROID_BUILD=1` when running Expo prebuild:
+
+```bash
+cd packages/app
+PASEO_FDROID_BUILD=1 APP_VARIANT=production npx expo prebuild --platform android --clean --non-interactive
+cd android
+./gradlew assembleRelease
+```
+
+That env var is intentionally narrow. It enables `expo.autolinking.android.buildFromSource: [".*"]` so Expo modules are built from source instead of linked from precompiled AARs, and it applies `expo-gradle-jvmargs` with `-Xmx4096m` and `-XX:MaxMetaspaceSize=1024m` for the larger source build. Normal local and EAS builds leave those settings off.
+
 ### React version lockstep
 
 Keep `react` and `react-dom` pinned to the React version embedded by the current `react-native` release. React Native `0.81.x` embeds `react-native-renderer` `19.1.0`, so `packages/app` must use React `19.1.0`. Bumping React to a newer patch can build successfully but crash at JS startup on Android with `Incompatible React versions`, leaving the app on the native splash screen.
diff --git a/docs/release.md b/docs/release.md
index 668ba5782e..bd572bb6a3 100644
--- a/docs/release.md
+++ b/docs/release.md
@@ -188,6 +188,8 @@ iOS and Android store builds are not in `.github/workflows`. They are triggered
 - **iOS (TestFlight + App Store)** — EAS builds with profile `production`, uploads to TestFlight, and a Fastlane lane submits the build for App Store review.
 - **Android APK (GitHub Release asset)** — separate, via `.github/workflows/android-apk-release.yml`. This is the only Android-related workflow that lives in this repo.
 
+EAS uses the local app version source. `packages/app/app.config.js` derives Android `versionCode` and iOS `buildNumber` from the package version as `1_000_000 + major * 1_000_000 + minor * 1_000 + patch`, ignoring prerelease metadata. Rebuilding the same tag produces the same native build number; if a store has already accepted a binary and you need a different binary, cut a new patch instead of relying on EAS remote auto-increment.
+
 There is no `release-mobile.yml` in this repo. Earlier versions of these docs referenced one — that workflow was removed and the EAS GitHub app handles tag triggering directly.
 
 ### Watching mobile builds from the terminal
diff --git a/package-lock.json b/package-lock.json
index 86163beb9f..8763f5dd44 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -19591,6 +19591,16 @@
         "react-native": "*"
       }
     },
+    "node_modules/expo-gradle-jvmargs": {
+      "version": "1.1.2",
+      "resolved": "https://registry.npmjs.org/expo-gradle-jvmargs/-/expo-gradle-jvmargs-1.1.2.tgz",
+      "integrity": "sha512-VJRecrYlklVXEwafLyuZKUCnYEY9vJYvUy639LN3c5krlmunkYQphh/YzXDng8C9oihz6mr+cPbwEn6sv6fXyw==",
+      "dev": true,
+      "license": "MIT",
+      "peerDependencies": {
+        "@expo/config-plugins": "*"
+      }
+    },
     "node_modules/expo-haptics": {
       "version": "15.0.8",
       "resolved": "https://registry.npmjs.org/expo-haptics/-/expo-haptics-15.0.8.tgz",
@@ -35250,6 +35260,7 @@
         "eas-cli": "^16.24.1",
         "eslint": "^9.25.0",
         "eslint-config-expo": "~10.0.0",
+        "expo-gradle-jvmargs": "^1.1.2",
         "jsdom": "^20.0.3",
         "material-icon-theme": "^5.32.0",
         "playwright": "^1.56.1",
diff --git a/packages/app/app.config.js b/packages/app/app.config.js
index 959fb27f01..7409ee2883 100644
--- a/packages/app/app.config.js
+++ b/packages/app/app.config.js
@@ -2,6 +2,32 @@ const fs = require("node:fs");
 const path = require("node:path");
 const pkg = require("./package.json");
 const appVariant = process.env.APP_VARIANT ?? "production";
+const isFdroidBuild = process.env.PASEO_FDROID_BUILD === "1";
+const nativeBuildVersionFloor = 1_000_000;
+
+function getNativeBuildVersionCode(version) {
+  const match = /^(\d+)\.(\d+)\.(\d+)(?:[-+].*)?$/.exec(version);
+  if (!match) {
+    throw new Error(`Cannot derive Android versionCode from non-semver version: ${version}`);
+  }
+
+  const [, majorText, minorText, patchText] = match;
+  const major = Number(majorText);
+  const minor = Number(minorText);
+  const patch = Number(patchText);
+
+  if (minor > 999 || patch > 999) {
+    throw new Error(`Cannot derive collision-free Android versionCode from version: ${version}`);
+  }
+
+  const versionCode = nativeBuildVersionFloor + major * 1_000_000 + minor * 1_000 + patch;
+
+  if (!Number.isSafeInteger(versionCode) || versionCode <= 0 || versionCode > 2_100_000_000) {
+    throw new Error(`Derived Android versionCode is out of range: ${versionCode}`);
+  }
+
+  return versionCode;
+}
 
 function resolveSecretFile(params) {
   const fromEnv = process.env[params.envKey];
@@ -45,6 +71,7 @@ const variants = {
 };
 
 const variant = variants[appVariant] ?? variants.production;
+const nativeBuildVersionCode = getNativeBuildVersionCode(pkg.version);
 
 export default {
   expo: {
@@ -72,6 +99,7 @@ export default {
       ...(variant.googleServiceInfoPlist
         ? { googleServicesFile: variant.googleServiceInfoPlist }
         : {}),
+      buildNumber: String(nativeBuildVersionCode),
     },
     android: {
       adaptiveIcon: {
@@ -91,6 +119,7 @@ export default {
         "android.permission.CAMERA",
       ],
       package: variant.packageId,
+      versionCode: nativeBuildVersionCode,
       ...(variant.googleServicesFile ? { googleServicesFile: variant.googleServicesFile } : {}),
     },
     web: {
@@ -99,6 +128,13 @@ export default {
     },
     autolinking: {
       searchPaths: ["../../node_modules", "./node_modules"],
+      ...(isFdroidBuild
+        ? {
+            android: {
+              buildFromSource: [".*"],
+            },
+          }
+        : {}),
     },
     plugins: [
       "expo-router",
@@ -139,6 +175,17 @@ export default {
           },
         },
       ],
+      ...(isFdroidBuild
+        ? [
+            [
+              "expo-gradle-jvmargs",
+              {
+                xmx: "4096m",
+                maxMetaspace: "1024m",
+              },
+            ],
+          ]
+        : []),
     ],
     experiments: {
       typedRoutes: true,
diff --git a/packages/app/eas.json b/packages/app/eas.json
index 42f282fb63..805217b895 100644
--- a/packages/app/eas.json
+++ b/packages/app/eas.json
@@ -1,7 +1,7 @@
 {
   "cli": {
     "version": ">= 14.0.0",
-    "appVersionSource": "remote"
+    "appVersionSource": "local"
   },
   "build": {
     "development": {
@@ -19,9 +19,6 @@
       "channel": "production",
       "env": {
         "APP_VARIANT": "production"
-      },
-      "android": {
-        "autoIncrement": "versionCode"
       }
     },
     "production-apk": {
diff --git a/packages/app/package.json b/packages/app/package.json
index 0e0ef7a478..18072f824e 100644
--- a/packages/app/package.json
+++ b/packages/app/package.json
@@ -128,6 +128,7 @@
     "eas-cli": "^16.24.1",
     "eslint": "^9.25.0",
     "eslint-config-expo": "~10.0.0",
+    "expo-gradle-jvmargs": "^1.1.2",
     "jsdom": "^20.0.3",
     "material-icon-theme": "^5.32.0",
     "playwright": "^1.56.1",