Here's a cwcheat to disable the DLC signature checks in the European release version of WipEout Pure. This cheat will enable loading of "fake-signed" DLC (e.g. converted JAP or USA DLC) on the EUR version of the game. This has been tested on a real PSP-2004 with the UMD release of the game using cwcheat as well as PPSSPP (which has built-in support for cwcheat codes).
Note that it doesn't allow loading of unmodified out-of-region DLC -- the DLC needs to be re-encrypted with an EUR signature for this to work.
Code:
_S UCES-00001
_G WipeOut Pure [EU]
_C1 Remove DLC Signature Check
_L 0x200A6FC0 0x00000000
_L 0x200A70A0 0x00000000
For example, here's Coke Style (Japan-only DLC ship) on Burgertown (Europe-only DLC track):
cokestyle-eur.png