Hum, yeah looking at the code I won't understand enough how it's done to get something done by myself ^^

Hello, I found a solution. :)

I uninstall and reinstall the retropiemenu.

Copy the PSX gamelist.xml file to your PC and create a backup copy in case you get undesired results and you need to start over. Open the file in a text editor and use the Search for and Replace feature. Copy the file back to your pi after you have exited ES.