diff --git a/.septentrio/Jenkinsfile b/.septentrio/Jenkinsfile
index 6a105ec3dc16fa..d6e376de80ffb7 100644
--- a/.septentrio/Jenkinsfile
+++ b/.septentrio/Jenkinsfile
@@ -1,26 +1,38 @@
 pipeline {
     triggers {
+        // Poll the Git repository every 5 minutes to detect changes.
         pollSCM('H/5 * * * *')
     }
+    // Run stages without specified agent on any available agent.
     agent any
+    // Parameters used for manual builds triggered in the Jenkins web UI.
     parameters {
         string(name: 'BOARDS', defaultValue: 'Pixhawk6C Pixhawk6X', description: 'A space-separated list of boards to build for')
         
         string(name: 'GIT_REVISION', defaultValue: 'Copter-0.0.0-citesting', description: 'The Git revision (commit, branch, tag...) to check out')
     }
+    // Options for the pipeline.
     options {
+        // Discard old builds to save space.
         buildDiscarder logRotator(artifactDaysToKeepStr: '', artifactNumToKeepStr: '', daysToKeepStr: '1', numToKeepStr: '')
     }
     stages {
-        // Check out the repository on the Jenkins server
+        // Check out the repository on the Jenkins server.
         stage('Checkout') {
             steps{
-                git(branch: 'Copter-0.0.0-citesting', 
-                    url: 'https://github.com/flyingthingsintothings/ardupilot.git')
+                git(url: 'https://github.com/flyingthingsintothings/ardupilot.git')
                 echo "$GIT_COMMIT"
                 // We need all the tags locally to check them out. The documentation to do this with the builtin steps is not really useful.
                 sh "git fetch --all"
-                sh "git checkout ${params.GIT_REVISION}"
+                script {
+                    if (env.GIT_COMMIT) {
+                        // Build started from polling SCM.
+                        sh "git checkout $GIT_COMMIT"
+                    } else {
+                        // Build started by user with parameters.
+                        sh "git checkout ${params.GIT_REVISION}"
+                    }
+                }
                 sh "./Tools/gittools/submodule-sync.sh"
             }
         }