it takes time to upload the 17MB file. you need to stay on the upgrade page and wait. after upload, it will upgrade the system, and then get restarted automatically. during the process, do not switch to other tabs. or the upgrade will be terminated.
If after upgrading you still have die issues, you can power off the PSU and power on again. my neppy sometimes also has die issues. using web page to restart the miner does not work, but a hard restart solves the problem.
It just times out after a while/
Same from different browsers and different devices.
2nd die on first chip has not worked at any point; totally screwed I think.