why would you want a browser based firmware flasher? the web browser should surely not deal with hardware. you don't even get to know if the flashing code has changed, or verify it in Any way

I have already hated the grapheneos web flasher, even if its just made for those for whom themost basic computer terms area dufficult task, like download this file, type cmd into the start menu, press enter, paste this ~~command~~ text, press enter. but it could have been solved with a most simple gui executable too!