Magic Swap does not support PS1 games, in order to play PS1 backups on a Sensor modded Slimline, you need the following items:
1. A PS1 game
2. A PS1 backup
When you insert the retail PS1 game (does not matter what game), the PS1 logo will appear, make sure you keep the lid open throughout this entire procedure, right after the logo appears, the disc will slow down for a split second, when this happens. you need to quickly swap the PS1 backup with the PS1 retail and close the lid. The PS1 Slimline will think that the lid is still closed, therefore it thinks that it is still booting a retail PS1 game. This allows you to play any PS1 backup, even imported backups.