diff --git a/pkgs/applications/misc/yubioath-flutter/default.nix b/pkgs/applications/misc/yubioath-flutter/default.nix
index f1e0094468a7..3e2f8116a88d 100644
--- a/pkgs/applications/misc/yubioath-flutter/default.nix
+++ b/pkgs/applications/misc/yubioath-flutter/default.nix
@@ -21,7 +21,7 @@ flutter.mkFlutterApp rec {
 
   passthru.helper = python3.pkgs.callPackage ./helper.nix { inherit src version meta; };
 
-  vendorHash = "sha256-1ast8pm9wrt9nqLt5MJ2LkiZivlm9d+qcKrz/d8VVmI=";
+  vendorHash = "sha256-/WP6oN5avAILZd3SkC/jmsqNL+BxdQGUjNwsjLF9RB4=";
 
   postPatch = ''
     substituteInPlace linux/CMakeLists.txt \
diff --git a/pkgs/build-support/flutter/default.nix b/pkgs/build-support/flutter/default.nix
index 58149525b476..f83998f3f9f7 100644
--- a/pkgs/build-support/flutter/default.nix
+++ b/pkgs/build-support/flutter/default.nix
@@ -43,13 +43,9 @@ let
 
       RES="$TMP"
 
-      mkdir -p "$RES/f"
-
       # so we can use lock, diff yaml
       cp "pubspec.yaml" "$RES"
       cp "pubspec.lock" "$RES"
-      [[ -e .packages ]] && mv .packages "$RES/f"
-      mv .dart_tool .flutter-plugins .flutter-plugins-dependencies "$RES/f"
 
       # replace paths with placeholders
       find "$RES" -type f -exec sed -i \
@@ -57,30 +53,16 @@ let
         -e s,${flutter.unwrapped},${placeholder_flutter},g \
         {} +
 
-      remove_line_matching() {
-        replace_line_matching "$1" "$2" ""
-      }
-
-      replace_line_matching() {
-        sed "s|.*$2.*|$3|g" -r -i "$1"
-      }
-
       # nuke nondeterminism
 
-      # clientId is random
-      remove_line_matching "$RES/.flutter" clientId
-
       # deterministic git repos
       find "$RES" -iname .git -type d | while read -r repoGit; do
         make_deterministic_repo "$(dirname "$repoGit")"
       done
 
-      # dart _fetchedAt, etc
-      DART_DATE=$(date --date="@$SOURCE_DATE_EPOCH" -In | sed "s|,|.|g" | sed "s|+.*||g")
-      find "$RES/.pub-cache" -iname "*.json" -exec sed -r 's|.*_fetchedAt.*|    "_fetchedAt": "'"$DART_DATE"'",|g' -i {} +
-      replace_line_matching "$RES/f/.dart_tool/package_config.json" '"generated"' '"generated": "'"$DART_DATE"'",'
-      replace_line_matching "$RES/f/.flutter-plugins-dependencies" '"date_created"' '"date_created": "'"$DART_DATE"'",'
-      [[ -e "$RES/f/.packages" ]] && remove_line_matching "$RES/f/.packages" "Generated by pub"
+      # Impure Pub files
+      rm -rf "$RES"/.pub-cache/hosted/*/.cache # Not pinned by pubspec.lock
+      rm -f "$RES"/.pub-cache/README.md # May change with different Dart versions
 
       # nuke refs
       find "$RES" -type f -exec nuke-refs {} +
@@ -89,7 +71,7 @@ let
       tar --owner=0 --group=0 --numeric-owner --format=gnu \
           --sort=name --mtime="@$SOURCE_DATE_EPOCH" \
           -czf "$out" -C "$RES" \
-          pubspec.yaml pubspec.lock f .pub-cache
+          pubspec.yaml pubspec.lock .pub-cache
     '';
 
     GIT_SSL_CAINFO = "${cacert}/etc/ssl/certs/ca-bundle.crt";
@@ -148,8 +130,6 @@ let
     fi
     diff -u pubspec.yaml "$HOME/pubspec.yaml"
 
-    mv -v $(find "$HOME/f" -type f) .
-
     runHook postConfigure
   '';
 
diff --git a/pkgs/os-specific/linux/firmware/firmware-updater/default.nix b/pkgs/os-specific/linux/firmware/firmware-updater/default.nix
index 696704d3c4d4..12f5fe13a6a3 100644
--- a/pkgs/os-specific/linux/firmware/firmware-updater/default.nix
+++ b/pkgs/os-specific/linux/firmware/firmware-updater/default.nix
@@ -7,7 +7,7 @@ flutter2.mkFlutterApp {
   pname = "firmware-updater";
   version = "unstable";
 
-  vendorHash = "sha256-QPLAMFL/enMfbmUZx6qQSswI/vxeWgjytRdoNxziQ18=";
+  vendorHash = "sha256-Pj6CU2W5juk4YE8oq+v7Z8CzuSwpyA3YqscoWGDaI4o=";
 
   src = fetchFromGitHub {
     owner = "canonical";