Create a folder called "PS3" on the root of your USB flash drive
Create a folder within the PS3 folder called "UPDATE"
Extract MinVerChk into the UPDATE folder, ensure it is named "PS3UPDAT.PUP"
Plug flash drive into the right-most USB port on your PS3
On the XMB, navigate to "System Update" under Settings and choose "Update via Storage Media"
Run the update, and a message will appear stating "Update data of version ____ or later can be installed on this system". If this number is 3.56 or lower, your model is compatible with CFW. Consoles that report 3.56 still contain the original hardware keys for 3.55 and therefore are compatible with any CFW or OFW above 3.55.