diff --git a/.github/workflows/on_demand.yml b/.github/workflows/on_demand.yml
index cc5b85b1..646865d5 100644
--- a/.github/workflows/on_demand.yml
+++ b/.github/workflows/on_demand.yml
@@ -24,7 +24,7 @@ jobs:
         test/health.awk < log > json
         scp -o "StrictHostKeyChecking=no" json "root@176.9.217.245:/data/downloads/health/atcmd_${{ matrix.cc }}_$(date +"%Y%m%d").json"
   atcmd89:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04  # Ubuntu 26.04 Docker 29.4.2 breaks 32-bit Wine; switch at >= 29.4.3
     strategy:
       fail-fast: false
       matrix:
diff --git a/.github/workflows/quicktest.yml b/.github/workflows/quicktest.yml
index d21525c4..6a1cbaf3 100644
--- a/.github/workflows/quicktest.yml
+++ b/.github/workflows/quicktest.yml
@@ -83,7 +83,7 @@ jobs:
         /opt/homebrew/opt/mosquitto/sbin/mosquitto -c /Users/runner/work/mongoose/mongoose/test/mosquitto.conf.macos &
         make -C test test ASAN_OPTIONS=
   windows:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04  # Ubuntu 26.04 Docker 29.4.2 breaks 32-bit Wine; switch at >= 29.4.3
     strategy:
       fail-fast: false
       matrix: