Pic Unrelated.

I don't know if this is a good place to ask but I have a problem that's been screwing me over this past months. If it isn't, it'd be nice for someone to redirect me.

I own a wacom bamboo fun. That tablet's pen has two ends, the regular one and the eraser one. The regular one is broken. I tried to open it and fix it but I'm hopeless...

The thing is, I normally use SAI, but I think Photoshop is better to color with. Either way, when I use SAI I can use the eraser tip to use the pen tool and it does the work.

When I use photoshop with the eraser tip it automatically changes to eraser tool, and I can't work with that. How can I disable this auto-switch thing?

tl;dr - how to disable the auto-eraser from photoshop when using the eraser tip on a tablet.