I am playing it now on my 2.71 SE B.
^_^
It is pretty easy to do, although it does have six steps. This works with both new demos, so feel free to get both (I did).
Step One. Get Dark_AleX's Decriptor Test
here.
Step two. Get PDP Unpacker
here.
Step three. Using unpacker, unpack all files from the eboot to a single folder (makes things easier). Copy the DATA.PSP file to the root of your psp.
Step four. Run Dark_AleX's Decriptor, and take the file it creates (DATA_OUT.PSP in the root folder), and rename it to DATA.PSP. put this somewhere you can find it.
Step five. Get a hex editor (I like this
one, get it from
here), and open up the file you unpacked called "PARAM.SFO". Look for "2.81" or "2.82", and change it to "2.71". Save this file.
Step six. Using the PDP unpacker, choose NEW, then click on the ... buttons and find each part it needs. If you do not have the file it asks for, then you don't need it. (on a side note, you can make your own icons/backgrounds... whee!). Click the SAVE option, and this is your new EBOOT.PBP! Stick it in a folder (any name) inside game, and your ready to go!
Link to Moto GP : FileFactory.com - free file hosting Link to LocoRoco : FileFactory.com - free file hosting