Managed to solve it this way:
Make a backup of all files (Menu/Misc/Backup all files)
Copy the memcards folder to a computer and load them with an emulator; in my case I used PCSX from the Ubuntu repos. The memcard saves were recognized on the fly and I was able to restart the game in the last save before the problem. I guess (actually hope) any other emulator will work but just in case, Ubuntu
is free, open source software, give it a try!
Continue the game and save after the problematic scene.
Copy the memcards folder from your computer to the SDcard on your phone.
In the Parameters Menu from FPSX set your memcards to the folder you just copied from your computer (Menu/Misc/Select memcard 1)
Load the game and voila!