diff --git a/bin/internal/dart-sdk.version b/bin/internal/dart-sdk.version
index 8df310ccc1..ae55a2b579 100644
--- a/bin/internal/dart-sdk.version
+++ b/bin/internal/dart-sdk.version
@@ -1 +1 @@
-1.21.0-dev.3.0
+1.21.0-dev.6.0
diff --git a/packages/flutter_tools/pubspec.yaml b/packages/flutter_tools/pubspec.yaml
index b716b7dda5..940b45b3a0 100644
--- a/packages/flutter_tools/pubspec.yaml
+++ b/packages/flutter_tools/pubspec.yaml
@@ -16,10 +16,8 @@ dependencies:
   http: ^0.11.3
   json_rpc_2: ^2.0.0
 
-  # Version 1.0.4 has mysterious "pub get" spam about "drudge". If you update
-  # this dependency, be sure not to include 1.0.4 and to check the output of
-  # "pub get" for spam about "drudge".
-  json_schema: 1.0.3
+  # Versions 1.0.4 and below have duplicate pubspec map entries and will fail the build.
+  json_schema: 1.0.5
 
   linter: ^0.1.21
   meta: ^1.0.3