diff --git a/.github/scripts/prepare-vagrant-box-masters.sh b/.github/scripts/prepare-vagrant-box-masters.sh
index ce65ce4..9b92001 100755
--- a/.github/scripts/prepare-vagrant-box-masters.sh
+++ b/.github/scripts/prepare-vagrant-box-masters.sh
@@ -76,8 +76,7 @@ write_prewarm_vagrantfile() {
     if [[ "$box" == 'generic/ubuntu2204' ]]; then
       printf '%s\n' \
         '  config.ssh.username = "vagrant"' \
-        '  config.ssh.password = "vagrant"' \
-        '  config.ssh.insert_key = false'
+        '  config.ssh.password = "vagrant"'
     fi
     printf '%s\n' \
       '  config.vm.synced_folder ".", "/vagrant", disabled: true' \
@@ -85,8 +84,8 @@ write_prewarm_vagrantfile() {
       '  config.vm.boot_timeout = 600' \
       '  config.vm.provider "virtualbox" do |virtualbox|' \
       '    virtualbox.linked_clone = true' \
-      '    virtualbox.memory = 512' \
-      '    virtualbox.cpus = 1' \
+      '    virtualbox.memory = 1024' \
+      '    virtualbox.cpus = 2' \
       '  end' \
       'end'
   } > "$destination"
diff --git a/.github/scripts/test-prepare-vagrant-box-masters.sh b/.github/scripts/test-prepare-vagrant-box-masters.sh
index a3b857e..d921d52 100755
--- a/.github/scripts/test-prepare-vagrant-box-masters.sh
+++ b/.github/scripts/test-prepare-vagrant-box-masters.sh
@@ -47,7 +47,12 @@ third_output="$fixture/third-output"
 "$script" > "$first_output"
 grep -Fq 'config.ssh.username = "vagrant"' "$MOCK_VAGRANTFILE_CAPTURE"
 grep -Fq 'config.ssh.password = "vagrant"' "$MOCK_VAGRANTFILE_CAPTURE"
-grep -Fq 'config.ssh.insert_key = false' "$MOCK_VAGRANTFILE_CAPTURE"
+if grep -Fq 'config.ssh.insert_key' "$MOCK_VAGRANTFILE_CAPTURE"; then
+  printf 'prewarm Vagrantfile unexpectedly overrides Vagrant SSH key insertion\n' >&2
+  exit 1
+fi
+grep -Fq 'virtualbox.memory = 1024' "$MOCK_VAGRANTFILE_CAPTURE"
+grep -Fq 'virtualbox.cpus = 2' "$MOCK_VAGRANTFILE_CAPTURE"
 grep -Fq 'config.vm.boot_timeout = 600' "$MOCK_VAGRANTFILE_CAPTURE"
 mapping_file="$mock_master_root/generic_ubuntu2204-4.3.12-amd64.uuid"
 test -s "$mapping_file"