@demonscythe please post a new topic with details of your setup.

See https://retropie.org.uk/forum/topic/3/read-this-first

Think I may have been a bit dim - I was originally adding extra inputs and it didn't do anything, I've since overwrote all of them and it is reading the input now. Thanks for your help folks.

Thank you very much @herb_fargus , could you speak a little bit about the option or about the new wiki article in a short blog post? When I searched PSP as a gamepad RetroPie I allways saw only pages about the PSP emulators, there is also a Wi-Fi gamepad homebrew app but I only saw it working for Windoes, it is called wificontroller, it is a Linux one but you need a script on Linux, could you check if you can add it to a RetroPie setup option along with the option to start ot at boot? You only need to search psp wireless gamepad linux at google