I found a Sony bdp-s6700 Blu-ray player with wifi and Bluetooth built in at Goodwill for $5. Everything seems to work just fine. it can update its firmware as Sony releases it via network or manually via USB, which is why I think custom firmware is possible. i haven't been able to find anything but old forms and nothing was released tho it showed a video of someone playing GBA games with a DualShock 4 controller! If anyone here can find anything I would really apricate it!