No you cant mate unless your already on 4.50 CFW. What you need to do is either, 1.) Buy an e3 Flasher to downgrade your PS3 to 3.55 OFW, 2.) Send it off to someone to downgrade it for you, or 3.) Buy one that's on 3.55 OFW or already Jailbroken.

Also I suggest checking out Vim's Topic as he does this Service.

couchviolater wrote If so how? And If I can't how can I down grade ?

You Need This Tool:
Forums/t=6159775/released-downgra...hrimp.html

You will need a programmer. Tool above is for Teensy++ 2.0 there about $25
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Console Model Must Be CECH-2500 or Lower:
CECH-3000 and CECH-4000 CANNOT Be Downgraded.

CECH-2500 Only 75% are downgrade-able check lowest firmware you can install with "MinVerChk".
Must be 3.55 or lower or else it cannot be downgraded.

MinVerChk Use:
Step 1: Download the [ Register or Signin to view external links. ] .
Step 2: Put the PS3UPDAT.PUP onto the USB Flash Drive in the PS3/UPDATE/ folder.
Step 3: Power on your PS3 and navigate to the "System Update" option in the settings
Step 4: Choose "Update Via Media Storage"
Step 5: Let the PS3 search for the update, once it's found it it will ask you if you'd like to run it. Hit "OK"
Step 6: It should only take a few seconds, a message will pop up telling you what the lowest firmware your PS3 can use!
Step 5: If lowest version is 3.55 or lower then your system is downgradable.