flutter screenshot fails on iOS 14 beta 5: Could not connect to screenshotr! #64605

$ flutter screenshot -d 00008027-001925360106802E
Error taking screenshot: ProcessException: Process exited abnormally:
Could not connect to screenshotr!
  Command: /Users/m/Projects/flutter/bin/cache/artifacts/libimobiledevice/idevicescreenshot /Users/m/Projects/gallery/flutter_01.png --udid 00008027-001925360106802E

[✓] Flutter (Channel master, 1.22.0-2.0.pre.57, on Mac OS X 10.15.5 19F101, locale en-US)
    • Flutter version 1.22.0-2.0.pre.57 at /Users/m/Projects/flutter
    • Framework revision e960d773ee (25 hours ago), 2020-08-24 17:48:05 -0700
    • Engine revision b792de7bae
    • Dart version 2.10.0 (build 2.10.0-56.0.dev)

 
[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
    • Android SDK at /Users/m/Library/Android/sdk
    • Platform android-30, build-tools 29.0.2
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 12.0)
    • Xcode at /Users/m/Applications/Xcode-12-beta6.app/Contents/Developer
    • Xcode 12.0, Build version 12A8189n
    • CocoaPods version 1.9.3

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 4.0)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 48.1.2
    • Dart plugin version 193.7361
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)

[✓] VS Code (version 1.47.3)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.13.2

[✓] Connected device (7 available)
    • iPhone 4s (mobile)     • 1754b457ae0324670be2493c147bf08bdad86907 • ios            • iOS 9.3.6
    • iPhone 6s (mobile)     • d83d5bc53967baa0ee18626ba87b6254b2ab5418 • ios            • iOS 13.5.1
    • Jenn iPad Pro (mobile) • 00008027-001925360106802E                • ios            • iOS 14.0
    • iPhone X (mobile)      • C9A36DF7-7034-48B5-AE15-2AA8E3F84B79     • ios            • com.apple.CoreSimulator.SimRuntime.iOS-12-4 (simulator)
    • macOS (desktop)        • macos                                    • darwin-x64     • Mac OS X 10.15.5 19F101
    • Web Server (web)       • web-server                               • web-javascript • Flutter Tools
    • Chrome (web)           • chrome                                   • web-javascript • Google Chrome 85.0.4183.83