Kodi doesn't work correctly, and /dev/root full at 100%

[fp69]

Hello,

Kodi doesn't work here, all the extensions can't be updated (the failed update always is shown)
I tried to understand why it doesn't work, and I think that I've got a track: /dev/root is full at 100%, it's 1,9 Go of size, mounted on the root directory.
What can I do to purge it without breaking recalbox and kodi?

I precise that the roms are all in a share mounted on a USB key.

Thanks in advance.