Help & troubleshooting for channels on your Roku device, including adding/removing channels, logging in to, authenticating, or activating a channel, channel-specific playback issues, assistance contacting channel publishers to report issues, and adjusting channel-specific settings.
There have been many reports of other units going through the same thing on initial setup and never completing.
A solution that has been reported to work is:
Setting up initially on a different network such as a wifi hotspot on a mobile phone, or at a neighbor's. If/when it completes the update successfully then they could switch it back to using their home wifi network.
This has not been universally successful, but many people have reported it worked for them.
Roku Streaming Stick +, 3810X, Ser YH0059427035, wifi - Samsung UN55ES6100
Roku Streaming Stick, 3600X, Ser 5S56D8240827, wifi - JVC EM37T