PS1 MC works on PS2, but doesn't show up

Hello. So I plug my memory cards into both of the ports, but yet it doesn't show up in the device menu. However, it works fine in the games, loads up without any issues. I should note that the memory cards are official PSOne and that I don't have a PS1 console with me anymore. The PS2 is a Slim.

Is there any solution to this problem? If not, is there another way to edit my MC? Like through a PS1 game or a FMCB app (I have FMCB)? Any help is appreciated.

Thanks in advance.