no more free method to convert it to Brown
That's right

I actually need to just Unlock the SIM lock of a CID53 Red C510 .I don't want to add or change any features or skin of the phone but just let me use other phone network.Can anyone help?
Thanks in advance
In this case, I recommend OMNIUS service, check this: Top Sony Forums - Buy Omnius License and this: Omnius.
Greetings