I had the same issue with the GUI and solved it both o Windows and Linux using the Pale Moon browser and java. The procedure is described below.
On Linux :
Install java (using a terminal with sudo):
1- Download jdk1.8.0.261 (mandatory) for your distribution - Later versions don't embed libnpjp2.so - and install it following standard procedure
https://www.oracle.com/fr/java/technologies/javase/javase8u211-later-archive-downloads.html
https://www.java.com/en/download/help/linux_x64_install.html
2 - Configure java to enable java execution for your switch :
in the terminal window, go to the directory where you have installed java, change directory to bin (cd bin), launch the Control Panel (./Control Panel). This will open a graphical interface to configure Java. In the security tab, add the address of your switch (e.g. htpp://192.168.1.1).
3 - Create a symbolic link for Pale Moon to access to libnpjp2.so :
Create the Mozilla plugins directory
- cd /usr/lib
- mkdir mozilla
- cd mozilla
- mkdir plugins
create the symbolic link to the library
- sudo ln -s /usr/java/jdk1.8.0_261//jre/lib/amd64/libnpjp2.so
4 - Install Pale Moon browser :
https://developer.palemoon.org/docs/linux-installation/
5 - Launch Pale Moon :
Enter your switch address.
You will be incited to update Java. I didn't try this and forbid the update. Accept the security risk. The switch page should be displayed after a few seconds.
On Windows :
1 - Install Java
Follow the standard installation procedure:
https://www.java.com/en/download/help/windows_manual_download.html
2 - Configure Java :
- type java in the launch pad, this will open the Java Control Panel
- go to the Security tab
- add your switch address in the Exception Site List
3 - Install Pale Moon :
https://www.palemoon.org/download.shtml
4 - Launch Pale Moon :
Enter you switch address.
You will be asked for permission to run the application. Click on run and you page should be displayed after a few seconds.
Many thanks to the Pale Moon developers who maintain this browser and enabled me to solve this issue.