iOS Dart VM Debug Crash Fix | Generated by AI
You’re hitting a known iOS / Dart VM interaction: the Dart VM in debug (JIT) mode needs to make memory pages executable at runtime, and recent iOS releases have tightened policies so mprotect(..., PROT_EXEC) fails with 13 (Permission denied). That causes the Dart VM to abort while finalizing code and produces the crash you pasted (SIGABRT). This is not a Flutter app bug in your code — it’s a platform (iOS / system policy) + VM mode mismatch. (GitHub)
Quick summary / root cause
- Debug builds use the Dart JIT (hot reload/hot restart) which needs to change memory protection to make generated machine code executable. iOS recent versions block that, causing
mprotect failed: 13 (Permission denied)and an assert in the Dart VM. (GitHub)
Immediate workarounds (pick one that fits your workflow)
-
Run on Simulator — the simulator runs x86/arm simulator code where the JIT restrictions aren’t enforced, so debug + hot reload works. Command:
flutter run -d <simulator-id>(or open from Xcode). (GitHub) -
Use profile or release (AOT) on device — build AOT code so VM doesn’t need to mprotect pages at runtime. You lose hot reload but the app will run on-device.
- For a test install:
flutter build ios --releasethen install via Xcode orflutter install --release. - Or
flutter run --profile/flutter run --releaseto run directly. (GitHub)
- For a test install:
-
Use an older iOS device/OS (only as temporary testing): the restriction showed up in some iOS beta/versions; devices running an iOS version before the stricter policy won’t hit the assert. (Not ideal for long-term.) (Stack Overflow)
Longer-term fixes / recommendations
-
Update iOS / Xcode — Apple has changed behavior across beta releases; sometimes later iOS beta patches restore behavior or change the policy. If you’re on an iOS beta that introduced the restriction, update to the version that contains the fix. (See reports that certain iOS betas introduced/regressed this and later betas fixed or changed behavior.) (Stack Overflow)
-
Upgrade Flutter/Dart to the latest stable — Flutter/Dart teams tracked this in GitHub issues and released updates/workarounds after the platform change; ensure your Flutter and Dart are up-to-date. After upgrading, run
flutter cleanand rebuild. (GitHub) -
Follow the upstream issue(s) — there are active Flutter issues and PRs about iOS JIT/mprotect failures. Subscribe to the Flutter issue threads to pick up permanent fixes or recommended dev workflows. (I can paste the links if you want.) (GitHub)
Extra note about the UIScene message you also saw
The UIScene lifecycle message at the top (“UIScene lifecycle will soon be required…”) is a warning from iOS about moving to the modern scene-based app lifecycle (iOS 13+). It’s unrelated to the mprotect crash. You can ignore it temporarily, or migrate to using Scenes (implement SceneDelegate / update Info.plist) if you want to remove the warning. It is not the cause of the SIGABRT. (GitHub)
Concrete step-by-step I recommend right now
-
If you need to keep hot reload: run on the simulator.
flutter run -d <simulator-id> -
If you want to test on the physical device now: build release/profile (AOT).
flutter run --release(orflutter build ios --release+ install) -
Update your environment: upgrade iOS (if on a beta with the bug), update Xcode, upgrade Flutter/Dart,
flutter clean, then retry on device. -
If you want, paste the output of
flutter doctor -vand the exact iOS / device version you’re testing on and I’ll give the most specific next steps (e.g., “this iOS version is known-broken — update to X.Y.Z or use release builds”).
Links / references (so you can follow the upstream discussion)
- GitHub Flutter issue tracking debug-mode JIT /
mprotect failed: 13(discussion & workarounds). (GitHub) - StackOverflow thread reporting same
mprotect failed: 13in iOS beta — suggests platform regression and iOS beta fixes. (Stack Overflow) - A blog/summary explaining the iOS 26 / Flutter friction and recommended dev options. (Medium)
If you want, I’ll:
- give the exact
fluttercommands for building a release IPA and installing on your device, or - check your
flutter doctor -vand your device OS version to recommend the single best action now.
Which would you prefer?