Actually Snatcher, you can't. It's Mandatory and here's why..
http://www.joystiq.com/2010/09/07/ps3-firmware-3-42-mandatory-update-available-now/
Another month, yet another PS3 firmware update. Little over one month since 3.41 (and two months since 3.40) comes yet another mandatory update for your PS3. Firmware 3.42 seemingly doesn't add any functionality to your system beyond the usual "system software stability," but it is required if you want to continue accessing the PlayStation Network or the PlayStation Store.
While unverified, this update may be a response to a recently-released jailbreak tool, which supposedly enables piracy on Sony's once-bulletproof system. We'll update this story if Sony provides any additional details on what this firmware does exactly.
http://www.joystiq.com/2010/09/07/ps3-firmware-3-42-mandatory-update-available-now/
