diff --git a/.gitea/actions/prepare-ram-ci/action.yml b/.gitea/actions/prepare-ram-ci/action.yml
new file mode 100644
index 0000000..f76652f
--- /dev/null
+++ b/.gitea/actions/prepare-ram-ci/action.yml
@@ -0,0 +1,102 @@
+name: Prepare RAM CI environment
+description: Keep RustDesk Linux build data and package caches in the RAM workspace
+
+runs:
+  using: composite
+  steps:
+    - name: Configure RAM CI environment
+      shell: bash
+      run: |
+        set -euo pipefail
+        set +x
+
+        # The runner must mount its workspace on executable tmpfs, as for Fluxer.
+        case "$(findmnt -n -o FSTYPE -T "$GITHUB_WORKSPACE")" in
+          tmpfs|ramfs) ;;
+          *) echo "ERROR: GITHUB_WORKSPACE must be backed by RAM (tmpfs/ramfs)."; exit 1 ;;
+        esac
+
+        normalize_url() {
+          local value="$1"
+          value="${value//$'\r'/}"
+          value="${value//$'\n'/}"
+          case "$value" in
+            \"*\") value="${value#\"}"; value="${value%\"}" ;;
+            \'*\') value="${value#\'}"; value="${value%\'}" ;;
+          esac
+          test -n "$value" || { echo "ERROR: Nexus URL is empty" >&2; return 1; }
+          printf '%s/' "${value%/}"
+        }
+
+        NEXUS_CARGO_URL="$(normalize_url "${NEXUS_CARGO_URL:-}")"
+        NEXUS_MAVEN_URL="$(normalize_url "${NEXUS_MAVEN_URL:-}")"
+
+        # Preserve rustup and its proxies before moving HOME and Cargo caches.
+        # Unlike Fluxer, RustDesk selects multiple toolchains from upstream CI.
+        RUSTUP_HOME="${RUSTUP_HOME:-$HOME/.rustup}"
+        RUSTUP_EXE="$(command -v rustup)"
+        RUSTUP_BIN="$(dirname "$RUSTUP_EXE")"
+        CI_ROOT="$GITHUB_WORKSPACE/.ci"
+        mkdir -p "$CI_ROOT"/{home,tmp,cargo/bin,pub-cache,gradle/init.d,xdg-cache,xdg-config,xdg-data,vcpkg-cache,vcpkg-downloads}
+        chmod 700 "$CI_ROOT/home" "$CI_ROOT/cargo" "$CI_ROOT/gradle"
+
+        # Fail before cloning/building when the RAM mount is noexec.
+        printf '#!/bin/sh\nexit 0\n' > "$CI_ROOT/tmp/check-exec"
+        chmod +x "$CI_ROOT/tmp/check-exec"
+        "$CI_ROOT/tmp/check-exec"
+        rm "$CI_ROOT/tmp/check-exec"
+
+        cat > "$CI_ROOT/cargo/config.toml" <<EOF_CARGO
+        [source.crates-io]
+        replace-with = "cargo-proxy"
+
+        [source.cargo-proxy]
+        registry = "sparse+$NEXUS_CARGO_URL"
+        EOF_CARGO
+        chmod 600 "$CI_ROOT/cargo/config.toml"
+
+        cat > "$CI_ROOT/gradle/init.d/00-nexus.init.gradle" <<'EOF_GRADLE'
+        def nexusUrl = System.getenv("NEXUS_MAVEN_URL")
+        if (nexusUrl == null || nexusUrl.isBlank()) {
+            throw new GradleException("NEXUS_MAVEN_URL is not configured")
+        }
+        def configureNexusRepository = { repositories ->
+            repositories.maven {
+                name = "CI_NEXUS"
+                url = uri(nexusUrl)
+                allowInsecureProtocol = nexusUrl.startsWith("http://")
+            }
+        }
+        gradle.beforeSettings { settings ->
+            configureNexusRepository(settings.pluginManagement.repositories)
+            configureNexusRepository(settings.dependencyResolutionManagement.repositories)
+        }
+        EOF_GRADLE
+
+        {
+          echo "CI_ROOT=$CI_ROOT"
+          echo "HOME=$CI_ROOT/home"
+          echo "TMPDIR=$CI_ROOT/tmp"
+          echo "TMP=$CI_ROOT/tmp"
+          echo "TEMP=$CI_ROOT/tmp"
+          echo "XDG_CACHE_HOME=$CI_ROOT/xdg-cache"
+          echo "XDG_CONFIG_HOME=$CI_ROOT/xdg-config"
+          echo "XDG_DATA_HOME=$CI_ROOT/xdg-data"
+          echo "CARGO_HOME=$CI_ROOT/cargo"
+          # Upstream scripts expect rustdesk/target; do not move it elsewhere.
+          echo "CARGO_TARGET_DIR=$GITHUB_WORKSPACE/rustdesk/target"
+          echo "RUSTUP_HOME=$RUSTUP_HOME"
+          echo "PUB_CACHE=$CI_ROOT/pub-cache"
+          echo "GRADLE_USER_HOME=$CI_ROOT/gradle"
+          printf 'JAVA_TOOL_OPTIONS=%s -Djava.io.tmpdir="%s"\n' "${JAVA_TOOL_OPTIONS:-}" "$CI_ROOT/tmp"
+          echo "VCPKG_DEFAULT_BINARY_CACHE=$CI_ROOT/vcpkg-cache"
+          echo "VCPKG_DOWNLOADS=$CI_ROOT/vcpkg-downloads"
+          echo "NEXUS_CARGO_URL=$NEXUS_CARGO_URL"
+          echo "NEXUS_MAVEN_URL=$NEXUS_MAVEN_URL"
+        } >> "$GITHUB_ENV"
+        {
+          echo "$RUSTUP_BIN"
+          echo "$CI_ROOT/cargo/bin"
+        } >> "$GITHUB_PATH"
+
+        df -h "$GITHUB_WORKSPACE"
diff --git a/.gitea/workflows/android.yml b/.gitea/workflows/android.yml
index 477a450..94c99f6 100644
--- a/.gitea/workflows/android.yml
+++ b/.gitea/workflows/android.yml
@@ -7,6 +7,7 @@ on:
       - main
     paths:
       - ".gitea/workflows/android.yml"
+      - ".gitea/actions/prepare-ram-ci/**"
 
 env:
   # Change only this value to build another RustDesk tag/release.
@@ -20,9 +21,23 @@ env:
 jobs:
   build-android:
     name: Build RustDesk Android ARM64
-    runs-on: rustdesk-android
+    runs-on: ci-linux-builder
+
+    defaults:
+      run:
+        shell: bash
+
+    env:
+      NEXUS_CARGO_URL: ${{ secrets.NEXUS_CARGO_URL }}
+      NEXUS_MAVEN_URL: ${{ secrets.NEXUS_MAVEN_URL }}
 
     steps:
+      - name: Checkout CI repository
+        uses: actions/checkout@v4
+
+      - name: Prepare RAM CI environment
+        uses: ./.gitea/actions/prepare-ram-ci
+
       # -----------------------------------------------------------------------
       # RustDesk source
       # -----------------------------------------------------------------------
@@ -249,7 +264,13 @@ jobs:
               [ -n "${preferred}" ] &&
               [ "$(flutter_version "${preferred}")" = "${requested}" ]
             ); then
-              root="${preferred}"
+              # Flutter writes into its SDK cache and receives source patches.
+              # Copy the image SDK into RAM before using it.
+              root="${fallback}"
+              if [ ! -d "${root}" ]; then
+                mkdir -p "$(dirname "${root}")"
+                cp -a "${preferred}" "${root}"
+              fi
             else
               root="${fallback}"
 
@@ -397,8 +418,17 @@ jobs:
           echo
           echo "=== vcpkg ==="
 
-          test -n "${VCPKG_ROOT:-}"
-          test -d "${VCPKG_ROOT}/.git"
+          # Reuse the image checkout and prebuilt libraries in RAM when present.
+          image_vcpkg="${VCPKG_ROOT:-}"
+          export VCPKG_ROOT="${CI_ROOT}/vcpkg"
+          if [ ! -d "${VCPKG_ROOT}/.git" ]; then
+            if [ -n "${image_vcpkg}" ] && [ -d "${image_vcpkg}/.git" ]; then
+              cp -a "${image_vcpkg}" "${VCPKG_ROOT}"
+            else
+              git clone https://github.com/microsoft/vcpkg.git "${VCPKG_ROOT}"
+            fi
+          fi
+          echo "VCPKG_ROOT=${VCPKG_ROOT}" >> "${GITHUB_ENV}"
 
           current_vcpkg="$(
             git -C "${VCPKG_ROOT}" rev-parse HEAD