"Upgrading to ITMS 7.1 SP2 – MP1.1 – Best Practices":
http://www.symantec.com/docs/TECH197966
Apat from the usual stuff about emptying queues and backing up everything there's point 5:
"Backup the Copyfiles folder in the Deployment Share under Task Handlers"
And point 7 post implementation:
"Move FIRM.EXE into the correct location per TECH198111"
http://www.symantec.com/docs/TECH198111
Personally I always use xcopy instead of FIRM outside of DOS.