diff --git a/gce/jenkins-slave.sh b/gce/jenkins-slave.sh
index fc840a2..4a38245 100644
--- a/gce/jenkins-slave.sh
+++ b/gce/jenkins-slave.sh
@@ -1,4 +1,4 @@
-#!/usr/bin/env bash
+#!/bin/sh
 #
 # Copyright 2015 The Bazel Authors. All rights reserved.
 #
@@ -99,5 +99,23 @@
 
 EOF
 
+# As this init script is called before the setup is complete, we have to do
+# some dance to make sure we only start the actual script once bash (optional
+# on some systems) is installed.
+
+cat > /root/call-jenkins-startup <<'EOF'
+
+PATH=$PATH:/usr/local/bin ; export PATH
+echo `date` PATH=$PATH >> /root/early-startup.log
+
+while [ -z "`which bash`" ] ; do
+  echo `date` Waiting for bash to be installed >> /root/early-startup.log
+  sleep 60
+done
+
+bash /root/jenkins-startup
+
+EOF
+
 # Start the actual jenkins daemon
-echo bash /root/jenkins-startup | batch
+echo /bin/sh /root/call-jenkins-startup | batch
diff --git a/gce/vm.sh b/gce/vm.sh
index 9c7cb97..ceaaa62 100755
--- a/gce/vm.sh
+++ b/gce/vm.sh
@@ -63,10 +63,10 @@
     "freebsd-11-slave-2 https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-11-0-stable-amd64-2017-01-06 freebsd-11-2 europe-west1-d default startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
     "freebsd-11-slave-3 https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-11-0-stable-amd64-2017-01-06 freebsd-11-3 europe-west1-d default startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
     "freebsd-11-slave-4 https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-11-0-stable-amd64-2017-01-06 freebsd-11-4 europe-west1-d default startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
-    "freebsd-12-slave-1 https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-12-0-current-amd64-2017-07-04 freebsd-12-1 europe-west1-d default startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
-    "freebsd-12-slave-2 https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-12-0-current-amd64-2017-07-04 freebsd-12-2 europe-west1-d default startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
-    "freebsd-12-slave-3 https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-12-0-current-amd64-2017-07-04 freebsd-12-3 europe-west1-d default startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
-    "freebsd-12-slave-4 https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-12-0-current-amd64-2017-07-04 freebsd-12-4 europe-west1-d default startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
+    "freebsd-12-slave-1 https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-12-0-current-amd64-2017-10-31 freebsd-12-1 europe-west1-d default startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
+    "freebsd-12-slave-2 https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-12-0-current-amd64-2017-10-31 freebsd-12-2 europe-west1-d default startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
+    "freebsd-12-slave-3 https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-12-0-current-amd64-2017-10-31 freebsd-12-3 europe-west1-d default startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
+    "freebsd-12-slave-4 https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-12-0-current-amd64-2017-10-31 freebsd-12-4 europe-west1-d default startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
     # Fow Windows, we use a custom image with pre-installed MSVC.
     "windows-slave-1 windows-server-2012-r2-dc-v20160112-vs2015-cpp-python-msys windows-x86_64-1 europe-west1-d default windows-startup-script-ps1=jenkins-slave-windows.ps1"
     "windows-slave-2 windows-server-2012-r2-dc-v20160112-vs2015-cpp-python-msys windows-x86_64-2 europe-west1-d default windows-startup-script-ps1=jenkins-slave-windows.ps1"
@@ -100,7 +100,7 @@
     "ubuntu-16-04-slave-staging $UBUNTU1604 ubuntu_16.04-x86_64-staging europe-west1-d staging startup-script=jenkins-slave.sh ubuntu-16-04-slave.sh bootstrap-bazel.sh linux-android.sh cleanup-install.sh"
     "ubuntu-docker-slave-staging $UBUNTU1604 ubuntu_16.04-x86_64-docker-staging europe-west1-d default startup-script=jenkins-slave.sh ubuntu-16-04-slave.sh ubuntu-16-04-docker.sh bootstrap-bazel.sh linux-android.sh cleanup-install.sh"
     "freebsd-11-slave-staging https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-11-0-stable-amd64-2017-01-06 freebsd-11-staging europe-west1-d staging startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
-    "freebsd-12-slave-staging https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-12-0-current-amd64-2017-07-04 freebsd-12-staging europe-west1-d staging startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
+    "freebsd-12-slave-staging https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-12-0-current-amd64-2017-10-31 freebsd-12-staging europe-west1-d staging startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
     # Fow Windows, we use a custom image with pre-installed MSVC.
     "windows-slave-staging windows-server-2012-r2-dc-v20160112-vs2015-cpp-python-msys windows-x86_64-staging europe-west1-d staging windows-startup-script-ps1=jenkins-slave-windows.ps1"
     # Remote Cache
@@ -180,6 +180,9 @@
     freebsd*) # FreeBSD
       # Wait a bit for the VM to fully start
       wait_vm "$TAG" "$LOCATION" 120 /usr/bin/true
+      # Install bash directly calling gcloud, as the ssh_command function
+      # already depends on bash being installed and in PATH.
+      gcloud compute ssh --zone="${LOCATION}" --command "sudo pkg install -y bash" "${TAG}"
       # Create the jenkins user, run additional set-up scripts and mark
       # the install process as finished.
       ssh_command "$TAG" "$LOCATION" \