I do find Ubuntu's LiveUSB useful at work as a part of my personal toolbox. Nothing like a nice clean environment to run a Linux-based antivirus scan, or rescue data from a unbootable system. Unfortunately, that also means I sometimes end up with using a serial mouse and that's rather inconvenient.
To get things running, you'll need to use mdetect and inputattach from terminal. First, install mdetect if it's not already available, then run it to get some info on your mouse:
~$ sudo apt-get install mdetect
~$ sudo mdetect
You should get something like the following:
/dev/psaux seems to be a legacy PS/2 device and is irrelevant here. The second line basically tells us the driver we need to activate the serial mouse.
Simply use inputattach to tell X.org what mouse driver to use for the mouse attached to the serial port:
~$ sudo inputattach --daemon --intellimouse /dev/ttyS0
/dev/ttyS0 is the first serial port (COM1). You may need to replace 0 with 1 (COM2) depending on your hardware.
To get a list of drivers supported by inputattach, run:
~$ inputattach --help
Making the activation permanent
If you're running from a LiveCD or LiveUSB with no persistence then there's not much you can do about running inputattach on every boot to get your serial mouse working unless you remaster the LiveCD. That's quite beyond the scope of this post.
For an installed environment however, you can add the inputattach command to /etc/rc.local so that the mouse gets activated on every system boot. Open /etc/rc.local with,
~$ sudo gedit /etc/rc.local
and add inputattach --intellimouse /dev/ttyS0 (change --intellimouse and /dev/ttyS0 accordingly) above the line that says exit 0 to make it work. Be sure to save the changes.
Serial Mouse Howto