diff --git a/README.md b/README.md
index 418f51f..df8a21e 100644
--- a/README.md
+++ b/README.md
@@ -7,8 +7,6 @@ The open app store powered by your social network
 ## Build from source
 
 ```bash
-# Using FVM (recommended for reproducible builds)
-# Note: do NOT use "stable" in FVM. This repo pins Flutter via .fvmrc.
 fvm install
 fvm flutter pub get
 fvm flutter build apk --split-per-abi --debug
@@ -21,6 +19,30 @@ flutter pub get
 flutter build apk --split-per-abi --debug
 ```
 
+## Reproducible builds
+
+This repo pins:
+
+- **Flutter** via `.fvmrc` (do not use `stable` in FVM)
+- **Dart/Flutter dependencies** via `pubspec.lock`
+- **Android toolchain** via Gradle/AGP, and expects **JDK 17**
+
+Build "proof" (prints versions + builds):
+
+```bash
+# Use JDK 17 (set JAVA_HOME in your environment/CI if needed)
+# Examples:
+# export JAVA_HOME=$(/usr/libexec/java_home -v 17)            # macOS
+# export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64         # Ubuntu/Debian
+java -version
+
+fvm install
+fvm flutter --version
+fvm flutter pub get --enforce-lockfile
+
+fvm flutter build apk --split-per-abi --release
+```
+
 APK will be available at `build/app/outputs/flutter-apk`.
 
 <a href="https://zapstore.dev/apps/naddr1qvzqqqr7pvpzq7xwd748yfjrsu5yuerm56fcn9tntmyv04w95etn0e23xrczvvraqqgxgetk9eaxzurnw3hhyefwv9c8qakg5jt">