It appears that the firmware selector page is not working properly. If you type in a device (that is known to be supported), it will auto-complete as expected, but then it will say "No model found" -- this seems to be true for all supported version in the dropdown.
I did not even know the Firmware selector even existed until now .
I pulled it up and typed in the same info you have in the photo and it list Kernel, Factory , sysupgrade.
Have you check to see if any browser extensions like no script are causing it not to work on your end ?
With my old 1.5 DSL I have had similar things like that happen alot.
Checking browser extensions Running ipconfig /flushdns , restarting web browser , restarting PC and flipping off and back on the surge protector for the DSL modem and router are the first things I start looking at .
Safari on Mac. I am not using any plug-ins/extensions, and there are no network wide issues with my access to the firmware selector page. I opened an incognito window and i worked, so something bad with the cache or cookies... I'll have to troubleshoot what is causing the issue, but it only affects that machine.