it does not replace the files in the flash of your psp. When the installer says install 2.71, it is referring to the files required for devhook to be able to emulate 2.71 by running the files that shud have been in the flash (the dump) but are in the memstick. when u install it, it's only churning up the dump for u to use devhook with.
the files would come up in dh/271 folder and the dh folder must be placed on the psp
Removable disk F:
-PSP
-DH
--271
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