diff --git a/.forgejo/actions/linux-setup/action.yml b/.forgejo/actions/linux-setup/action.yml
index a16be63..ec2f37f 100644
--- a/.forgejo/actions/linux-setup/action.yml
+++ b/.forgejo/actions/linux-setup/action.yml
@@ -35,7 +35,7 @@ runs:
       shell: bash
       run: |
         P="${FORGEJO_PATH:-$GITHUB_PATH}"
-        curl -fsSL https://bun.sh/install | bash -s "bun-v${BUN_VERSION}" >/dev/null
+        bash tools/ci-install-bun.sh
         echo "$HOME/.bun/bin" >> "$P"
         command -v rustup || curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --profile minimal
         echo "$HOME/.cargo/bin" >> "$P"
diff --git a/.forgejo/workflows/acceptance.yml b/.forgejo/workflows/acceptance.yml
index cc5cbb2..e6a4b22 100644
--- a/.forgejo/workflows/acceptance.yml
+++ b/.forgejo/workflows/acceptance.yml
@@ -33,7 +33,7 @@ jobs:
         if: ${{ matrix.platform == 'Linux' }}
         shell: bash
         run: |
-          curl -fsSL https://bun.sh/install | bash -s "bun-v${BUN_VERSION}" >/dev/null
+          bash tools/ci-install-bun.sh
           echo "$HOME/.bun/bin" >> "${FORGEJO_PATH:-$GITHUB_PATH}"
       - name: Acceptance matrix (Linux)
         if: ${{ matrix.platform == 'Linux' }}
@@ -97,7 +97,7 @@ jobs:
           path: acceptance-runs/Windows-bun
       - name: Matrix (markdown), red cells fail the job
         run: |
-          curl -fsSL https://bun.sh/install | bash -s "bun-v${BUN_VERSION}" >/dev/null
+          bash tools/ci-install-bun.sh
           export PATH="$HOME/.bun/bin:$PATH"
           V=$(bun tools/desktop-version.ts --print)
           mkdir -p out
diff --git a/.forgejo/workflows/ci.yml b/.forgejo/workflows/ci.yml
index d0d95da..ff134a6 100644
--- a/.forgejo/workflows/ci.yml
+++ b/.forgejo/workflows/ci.yml
@@ -102,7 +102,7 @@ jobs:
         if: ${{ matrix.platform == 'Linux' }}
         shell: bash
         run: |
-          curl -fsSL https://bun.sh/install | bash -s "bun-v${BUN_VERSION}" >/dev/null
+          bash tools/ci-install-bun.sh
           echo "$HOME/.bun/bin" >> "${FORGEJO_PATH:-$GITHUB_PATH}"
       - name: Acceptance matrix (Linux)
         if: ${{ matrix.platform == 'Linux' }}
@@ -371,7 +371,7 @@ jobs:
       - uses: actions/checkout@v4
       - name: Tools
         run: |
-          curl -fsSL https://bun.sh/install | bash -s "bun-v${BUN_VERSION}" >/dev/null
+          bash tools/ci-install-bun.sh
           echo "$HOME/.bun/bin" >> "${FORGEJO_PATH:-$GITHUB_PATH}"
       - uses: actions/download-artifact@v3
         with:
@@ -406,7 +406,7 @@ jobs:
       # no apt: the installers were scanned with the private terms in their own jobs; this job only records
       - name: Tools
         run: |
-          curl -fsSL https://bun.sh/install | bash -s "bun-v${BUN_VERSION}" >/dev/null
+          bash tools/ci-install-bun.sh
           echo "$HOME/.bun/bin" >> "${FORGEJO_PATH:-$GITHUB_PATH}"
           [ -n "$FORGEJO_TOKEN" ] || { echo "secret RELEASE_TOKEN is missing (repo Settings > Actions > Secrets)" >&2; exit 1; }
       - uses: actions/download-artifact@v3
diff --git a/.forgejo/workflows/release.yml b/.forgejo/workflows/release.yml
index ee88ef0..e77a9fd 100644
--- a/.forgejo/workflows/release.yml
+++ b/.forgejo/workflows/release.yml
@@ -61,7 +61,7 @@ jobs:
       - name: Tag, package.json version, every version copy and the CHANGELOG agree
         id: check
         run: |
-          curl -fsSL https://bun.sh/install | bash -s "bun-v${BUN_VERSION}" >/dev/null
+          bash tools/ci-install-bun.sh
           echo "$HOME/.bun/bin" >> "${FORGEJO_PATH:-$GITHUB_PATH}"
           export PATH="$HOME/.bun/bin:$PATH"
           bun tools/desktop-version.ts
diff --git a/tools/ci-install-bun.sh b/tools/ci-install-bun.sh
new file mode 100644
index 0000000..8071050
--- /dev/null
+++ b/tools/ci-install-bun.sh
@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+# Installs bun $1 (or $BUN_VERSION) into ~/.bun/bin on a Linux CI runner from the npm registry (@oven/bun-linux-<arch>),
+# because GitHub's oven-sh/bun release assets answer 504 now and then; bun.sh/install with retries is the fallback.
+set -u
+V="${1:-${BUN_VERSION:?BUN_VERSION}}"
+case "$(uname -m)" in aarch64|arm64) A=aarch64 ;; *) A=x64 ;; esac
+D="$HOME/.bun/bin"; mkdir -p "$D"; T=$(mktemp -d)
+for i in 1 2 3; do
+  if curl -fsSL --max-time 120 "https://registry.npmjs.org/@oven/bun-linux-$A/-/bun-linux-$A-$V.tgz" | tar -xz -C "$T" \
+    && install -m 755 "$T/package/bin/bun" "$D/bun"; then ln -sf bun "$D/bunx"; "$D/bun" --version; exit 0; fi
+  sleep 10
+done
+for i in 1 2 3; do curl -fsSL https://bun.sh/install | bash -s "bun-v$V" >/dev/null && { "$D/bun" --version; exit 0; }; sleep 20; done
+echo "bun $V: npm registry and GitHub both failed" >&2; exit 1