WFR responded to my help ticket and said it was OK to update without updating the Bullet2. Part of the reason I wanted to go to the forum was because they had previously told me I should update it because of connection problems I was having. I thought this WFR update would be a good excuse to finally getting around to updating the Bullet. This time they told me not to update it.
I watched the FB video again. I now know what they meant when they said to update WiFi Ranger devices first - they don't think of the Bullet they sold me as a WFR device.
The 6.6.5 update ran fine but I'm not using it as I'm parked for a while. I prefer my Dlink router / AP.
Thanks to everyone who replied.