If you are transfering your 3.55+ ps3 to your 3.55 CFW ps3 you need a spoofer you can get it here: You must login or register to view this content.

But if you are transfering the other way (3.55 to the 3.55+) and it doesnt work.
you should just go to internet Settings and press internet connection (off) on both ps3s
If it dosnt still work be sure that you use a working or a real Ethernet Cable like this one: You must login or register to view this content.

Hope it works out! have a good day mate!

You Must be doing something wrong, You need a spoofer as it says above. If it still does not work you probably have the cables mixed up, or you havnt got enough space on your 4.31 Hope this helps, if not try searching up your problem on youtube maybe... ^_^ Bye!