I'm going to perform a memory upgrade on a SQL2005 database mirror configuration running in High Protection (Synchronous) mode.
As far as I am concerned, I can power down the mirror, insert the new memory, power up the mirror and wait for the session to resync. Following the reconfiguration of the SQL min / max memory settings, I can manually fail over between the servers and perform the same actions again on the new mirror (old principal).
Aside from temporarily disabling the transaction log backups, I don't see any need to pause the mirroring session.
Just a quick sanity check to make sure that I am not missing out something obvious!