diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 19dc9943..d1b11f20 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -111,7 +111,16 @@ jobs:
         uses: Swatinem/rust-cache@v2
 
       - name: Install Trunk
-        uses: jetli/trunk-action@v0.5.0
+        # v0.5.0 selects the download by PLATFORM ONLY and never consults the
+        # architecture -- `case 'linux': arch = 'x86_64-unknown-linux-gnu'` --
+        # so on this aarch64 runner it fetches an x86_64 binary. v0.5.1 adds
+        # `process.arch` with 'x64' -> 'x86_64', 'arm64' -> 'aarch64' and
+        # core.setFailed otherwise, so a wrong arch now fails loudly instead of
+        # silently. It also moves the download host thedodd/trunk ->
+        # trunk-rs/trunk (trunk moved repositories; v0.5.0 still points at the
+        # old one), and swaps io.mv for io.cp, which is what avoids EXDEV on a
+        # self-hosted runner whose /tmp is a separate filesystem -- ours.
+        uses: jetli/trunk-action@v0.5.1
 
       - name: Check WASM compile
         run: >