diff --git a/.github/workflows/android-ci.yml b/.github/workflows/android-ci.yml
index 64dacb19..99d3eb64 100644
--- a/.github/workflows/android-ci.yml
+++ b/.github/workflows/android-ci.yml
@@ -32,6 +32,21 @@ jobs:
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@v4
 
+      # bundleWebUi (a Gradle dep of preBuild) shells out to
+      # scripts/build-web-ui.sh, which runs `npm run build` in desktop/. That
+      # invokes electron-builder for ALL configured Linux targets
+      # (AppImage + deb + rpm + pacman), so the runner needs rpm + bsdtar
+      # even though Android doesn't consume the installers. PR #98 added
+      # pacman+rpm targets without updating this workflow; every Android CI
+      # run since 2026-05-20 has been red on bsdtar exit 127.
+      #   libarchive-tools -> provides bsdtar (pacman target)
+      #   rpm              -> rpm target
+      - name: Install Linux build deps
+        # `apt-get update` prefix: the cached package index on ubuntu-latest
+        # often points to .deb versions that have rolled off the mirror, so
+        # a bare install hits HTTP 404 / exit 100. Refresh the index first.
+        run: sudo apt-get update && sudo apt-get install -y rpm libarchive-tools
+
       - name: Run unit tests
         run: ./gradlew test
 
diff --git a/.github/workflows/android-test-build.yml b/.github/workflows/android-test-build.yml
index f13ce88a..296a1b95 100644
--- a/.github/workflows/android-test-build.yml
+++ b/.github/workflows/android-test-build.yml
@@ -26,6 +26,16 @@ jobs:
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@v4
 
+      # build-web-ui.sh runs `npm run build` in desktop/, which invokes
+      # electron-builder for all configured Linux targets. Pacman needs
+      # bsdtar (libarchive-tools); rpm target needs the rpm package. See
+      # android-ci.yml for the full backstory on the PR #98 regression.
+      - name: Install Linux build deps
+        # `apt-get update` prefix: the cached package index on ubuntu-latest
+        # often points to .deb versions that have rolled off the mirror, so
+        # a bare install hits HTTP 404 / exit 100. Refresh the index first.
+        run: sudo apt-get update && sudo apt-get install -y rpm libarchive-tools
+
       # Build the full React UI so the APK has a working WebView.
       # bundleWebUi (Gradle preBuild dep) would do this too, but running
       # it explicitly here keeps this workflow's intent self-documenting.
diff --git a/.github/workflows/desktop-ci.yml b/.github/workflows/desktop-ci.yml
index fdc0d2f9..979f8143 100644
--- a/.github/workflows/desktop-ci.yml
+++ b/.github/workflows/desktop-ci.yml
@@ -27,5 +27,20 @@ jobs:
       - name: Run tests
         run: npm test
 
+      # Must run BEFORE the build — electron-builder's deb/rpm/pacman packagers
+      # run inside `npm run build` (see desktop/electron-builder.yml linux.target).
+      # PR #98 added rpm + pacman targets without updating CI, so every Desktop
+      # CI run since 2026-05-20 (commit 4679cc89) has been red on the same
+      # bsdtar-missing failure. Mirror desktop-release.yml's setup step:
+      #   libarchive-tools -> provides bsdtar, required by the pacman target
+      #   rpm              -> required by the rpm target
+      - name: Install Linux build deps
+        # apt-get update prefix: the cached package index on ubuntu-latest
+        # frequently points to .deb versions that have already rolled off
+        # the mirror, so a bare `install` fails with HTTP 404 / exit 100.
+        # Refresh the index first.
+        run: sudo apt-get update && sudo apt-get install -y rpm libarchive-tools
+        working-directory: .
+
       - name: Build
         run: npm run build
diff --git a/.github/workflows/desktop-test-build.yml b/.github/workflows/desktop-test-build.yml
index 0abb0a4e..6216b11f 100644
--- a/.github/workflows/desktop-test-build.yml
+++ b/.github/workflows/desktop-test-build.yml
@@ -39,6 +39,16 @@ jobs:
       - name: Run tests
         run: npm test
 
+      # Must run BEFORE the build — electron-builder's deb/rpm/pacman packagers
+      # run inside `npm run build`. See desktop-ci.yml for the PR #98 backstory.
+      - name: Install Linux build deps
+        if: runner.os == 'Linux'
+        # `apt-get update` prefix: the cached package index on ubuntu-latest
+        # often points to .deb versions that have rolled off the mirror, so
+        # a bare install hits HTTP 404 / exit 100. Refresh the index first.
+        run: sudo apt-get update && sudo apt-get install -y rpm libarchive-tools
+        working-directory: .
+
       - name: Build
         run: npm run build