Can you help me with something please? I have an original firmware that is 4.21 and i want to know if the official jailbreak KMEAW of 4.21 CFW has been released in order to play games downloaded from the internet. I don't want to brick my ps3 or to harm my settings, but i want to be sure of it because i don't want to harm my ps3.
There is no KMEAW 4.21 CFW or any other 4.21 CFW.. The highest is 3.55
You would have to use hardware flasher such as progskeet, e3flasher to downgrade your PS3, but first one has to run MinVerChk to see what the lowest firmware your Ps3 came with. You don't state if you have slim or FAT.
Other than that if it can be downgraded, you could alternatively pay someone to downgrade for you.