problem loading cape overlay with Debian 8.2

I am able to add a UART2 cape over lay in Debian 7.x but when I try with Debian 8.x I am not having much luck.

For example, if I type: echo BB-UART2 > /sys/devices/platform/bone_capemgr/slots
I get error: echo: write error: File exists

Any suggestions. I can’t figure this out.