Beryl/MT1300 cannot change configuration in WebUI

this applies to all configuration changes as they cannot be written to ‘disk’ anymore
Beryl/MT1300, 3.216 (2023-03-21 17:35:08), Firefox 112.14.0esr.

Suddenly (didn’t happen 5 days ago doing the same) when switching Block (internet access) on or off in CLIENTS area it says “SUCCESS!” but switches back to old state within seconds.
In the time between 5-days-ago and today I did not touch any other setting or accessed the command line.
Same when enabling Block for other devices, it’s reset within seconds to the old state.
Reboot didn’t help.

Any idea other than manually editing the config with vi?

found the cause when logging in via SSH: Your JFFS2-partition seems full and overlayfs is mounted read-only. Please try to remove files from /overlay/upper/... and reboot!

Such should be reported in the webUI as well, not every user has the ability to access the CLI.