if you open cex2dex.exe
on first slot select your flash dump from MM or E3
on second slot selct your rootkey from 3.55..but sometimes its not show the file..the put *.* to show all files on the folder
go to rebug website and download rebug toolbox update install it on ps3 then go to the toolbox and change XMB to Debug and everthing else to DEX or rebug then it should be spoofed to 4.40 then sign in