Follow these steps to update the firmware of your Grandstream HT801 1st generation device.
Then you should see Provision: Running, Status: Downloading file from url. (screenshot below). Just let it run.
The update will take some time. But after awhile you will be redirected to login again and to the following screen.
As you know the default password is admin, you will need to make a new one, the click Modify button.
Once you have changed your password, you will see that the firmware has updated and the Provision system is not running. This means, it is done.