diff --git a/.gitea/workflows/build.yaml b/.gitea/workflows/build.yaml
index 7e65ca7..824dd2e 100644
--- a/.gitea/workflows/build.yaml
+++ b/.gitea/workflows/build.yaml
@@ -15,7 +15,7 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-latest
     container:
       image: gitea.tourolle.paris/dtourolle/jellypod-builder:latest
 
diff --git a/.gitea/workflows/release.yaml b/.gitea/workflows/release.yaml
index f755665..d97a87b 100644
--- a/.gitea/workflows/release.yaml
+++ b/.gitea/workflows/release.yaml
@@ -13,7 +13,7 @@ on:
 
 jobs:
   build-and-release:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-latest
     container:
       image: gitea.tourolle.paris/dtourolle/jellypod-builder:latest
 
diff --git a/Dockerfile.build b/Dockerfile.build
index 30e1c05..1fc969e 100644
--- a/Dockerfile.build
+++ b/Dockerfile.build
@@ -1,3 +1,9 @@
+# Multi-arch (amd64 + arm64): CI runs on ubuntu-latest, which both the amd64 and the
+# ARM runners carry, so the image must exist for both.
+# Build + push (needs a docker-container buildx builder and arm64 binfmt/QEMU):
+#   docker buildx build -f Dockerfile.build --platform linux/amd64,linux/arm64 \
+#       -t gitea.tourolle.paris/dtourolle/jellypod-builder:latest --push .
+
 FROM mcr.microsoft.com/dotnet/sdk:10.0
 
 # Install Python, Node.js, and tools