Topic: Disable Networking to disable the update
Here's the workaround I used to disable the update notification.
1. Install the older firmware 1.7.1526 (see the other threads for instructions and link to the fw)
2. Boot up the Sony Dash
3. Configure the networking
4. Watch it fully boot up
5. Immediately unplug your internet connection at the wireless router OR disable internet some other way.
6. Now delete the wireless settings.
7. You can now enable the internet on your wireless router.
If between STEPS 4 & 5, it prompts you to update, you waited too long to disable the internet. Unplug the Sony Dash and reboot it. Repeat STEPS 4 + 5.