@politbureau You need to have access to the network to open the recalbox.conf and set emulationstation.hidesystemview=1 back to 0.
I don't know if it is possible without internet, MAYBE, if you use a Smartphone with Android, there is an option to share the internet (if you edit the network with the same name and password that you use at home), and use an explorer app files (like CX File Explorer) that give access to the network, but, I never tried, it is just an assumption.
What is your Hardware? If it is an Rpi, it is possible to put the SD card in the Smartphone, and navigate to the file recalbox.conf...