diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index f293f94..9ef92b6 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -13,10 +13,11 @@ jobs:
     if: github.event_name == 'workflow_dispatch' || contains(github.event.comment.body, '/release-action')
 
     steps:
-      - name: Update latest libnx
+      - name: Install libnx (pinned for toolchain compatibility)
         run: |
           git config --global --add safe.directory "*"
-          git clone --recurse-submodules https://github.com/zdm65477730/libnx.git
+          # Pin to a release tag; main branch requires newer newlib (RMutex.thread_tag) than container has
+          git clone --depth 1 --branch v4.6.0 --recurse-submodules https://github.com/switchbrew/libnx.git
           cd libnx
           make install -j$(nproc)
         shell: bash