I have no USB drives mounted, no user scripts running.
Just found a workaround though.... Pressing F5 to reload the page seems to have worked... updating firmware as we speak.
thanks for your fast reply.
About a month ago I replaced the stock firmware with Merlin 386_3_2 which works fine.
Today I wanted to upgrade it to 386_4 which is suggested.
But as soon as I visit the upgrade page (used chrome, firefox, edge on PC and Chrome on Pixel 6) a glass pane pops up "Downloading firmware" and that...