Let me elaborate GuilloteTesla's answer a bit - If you already have CFW you don't need to perform the jailbreak again as long as you don't install OFW or HFW by mistake.
Download Evilnat 4.90, put it on a MBR-FAT32 formatted USB drive as "PS3/UPDATE/PS3UPDAT.PUP" and perform a system update via storage. Make sure there's no game in the Blu-Ray drive when you do this. That's pretty much it.
