There have been a few questions along the same lines as this one, but
none of the previously suggested solutions work for me, unfortunately.

I have managed to get my mouse to work in the console with:

$ /usr/sbin/wsmoused -t microsoft -p /dev/cua00

but when I stop wsmoused and try to start X, I get the following
errors:

(==) Using config file: "/etc/X11/XF86Config"
(EE) xf86OpenSerial: Cannot open device /dev/cua00
Operation not permitted.
(EE) Mouse1: cannot open input device
(EE) PreInit failed for input device "Mouse1"
No core pointer

I have tried:
- changing /etc/fbtab to add /dev/cua00 to the /dev/ttyC0:
/dev/ttyC0 0600 /dev/console:/dev/wskbd:/dev/wsmouse:/dev/ttyCcfg:/dev/cua00

- changing the permissions/ownership of /dev/cua00 to all sorts,
including 0777.

- using different devices in XF86Config, all of them are dead (no
response, but no errors)

The relevant part of XF86Config:
Driver "mouse"
Option "Protocol" "microsoft"
Option "Device" "/dev/cua00"


Any help/tips appreciated!!