diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index e4c1b4d..5337d38 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -4,10 +4,9 @@ on:
   push:
     branches:
       - master
-  workflow_dispatch:
 
 env:
-  nixpkgs_channel: nixpkgs=channel:nixos-25.05
+  nixpkgs_channel: nixpkgs=channel:nixos-24.11
   oldest_supported_installer: nix-2.8.0
 
 jobs:
diff --git a/install-nix.sh b/install-nix.sh
index ba36ce0..3376733 100755
--- a/install-nix.sh
+++ b/install-nix.sh
@@ -94,7 +94,7 @@ echo "installer options: ${installer_options[*]}"
 
 # There is --retry-on-errors, but only newer curl versions support that
 curl_retries=5
-nix_version=2.30.2
+nix_version=2.30.1
 while ! curl -sS -o "$workdir/install" -v --fail -L "${INPUT_INSTALL_URL:-https://releases.nixos.org/nix/nix-${nix_version}/install}"
 do
   sleep 1