Motion sensor / gateway nuke lost drivers

[Aeternus90]

Hi, I'm playing Uplink on my Android tablet.

Here is my history:
- I've nuked my gateway
- I've re-bought the Trinity gateway
- I've re-bought all the software, filling my memory
- I've ordered the security systems
- I've ordered all the possible hw upgrades

Now, the security systems were installed with my memory full, so I couln't get the drivers. I've re-installed one of the two and got the driver, but having only three slots I couldn't re-install the second system.

How can I get the driver or remove one of the installed security systems in order to re-install it?