I just want to clarify, and I hope I am right here. If I am wrong you can taunt me

People are looking way to much at the numbers when trying to update to jailbreak. It does not matter if you are at 3.7 and want to go to CFW4.21. It does not matter if you are on OFW4.21 and want to go to CFW4.21

Those are just different firmware numbers and have nothing to do if you are able to update to rogeros firmware. The magic of all custom firmwares is in the 3.55 firmware. That was the last firmware from sony where it was able to downgrade, after 3.56 and so on they made some security in the firmwares.

To repeat again you have to have a ps3 with official firmware less than 3.55 or installed CFW3.55 before to be able to update, no other OFW will do the magic.

The only alternative is to flash the hardware and force 3.55 into the system.

Don't update to som OFW like 4.20 and think that "hell yeah, now my number on the firmware is pretty close to rogero, it should work"

I hope this is a correct explanation of it