about.hbs

{{bd-back-button}}

application.js

bd-back-button.hbs

<i class="bd-icon bd-icon--arrow-left"></i>

bd-back-button.js

import Ember from 'ember';
const { inject } = Ember;

export default Ember.Component.extend({
  tagName: 'a',
  classNames: ['button button--return'],
  attributeBindings: ['href', 'title'],
  history: inject.service(),

  click: function() {
    this.get('history').goBack();
  }
});

boot-history.js

// in instance-initializers/boot-history.js
//
// Not sure if this would work, but it would be interesting to see if
// this would let the history service capture the first willTransition
// event.

export function initialize(application) {
  application.container.lookup('service:history');
}

export default {
  name: 'boot-history',
  initialize: initialize
};

history.js

import Ember from 'ember';
const { inject } = Ember;

export default Ember.Service.extend({
  routing: inject.service('-routing'),
  
  // whatever stuff is already here
  
  init() {
    this._super(...arguments);
    this.get('routing.router').on('willTransition', (t) => this.capture(t));
  },
  
  goBack() {
    let previousTransition = this.get('previous');
    if (previousTransition) {
      this.capture(previousTransition);
      previousTransition.retry();
    } else {
      this.get('routing').transitionTo('home');
    }
  }
})