I just spent 10 hours updating 3 Oaks and eventually had success on all 3. The first one took 3 tries on my router (Netgear C3700-100NAS), the second 2 would not update with my router (through 1 wall, about 20 ft away). It said it failed updating the firmware every time.
I decided to hot-spot my phone and try that. This time success. When I used the SoftAP to log into my phone's hot-spot, I noticed the Oak connects, then disconnects, then connects again. This time, the Oak took more than the 60 second count-down to update the firmware (about 63 seconds as judged by the fast blinky LED). After updating firmware successfully, I shut down the hot-spot, power-cycled the Oak, then it went into AP mode where I used the SoftAP again to change the SSID/password for the Oak AP list back to my house router, and it worked fine.
Question: Is the **connect, then disconnect, then connect** having issues with some of the routers? I assume my phone (Samsung Galaxy S4) has a lot more processing power than my router, and had zero devices connected to it, while my router has about 6.