Wow, that's really nice of you. Here's what a found. I plugged my Adesso keyboard and played around with it. It has a built-in touchpad and the PS4 recognized it as a mouse, but it did not function - maybe just a problem keyboard, it's pretty old.
I'll try mapping them to the Flirc later on today.
PS4 interface:
Esc - back
F3 - Dual Shock 4 Options button
Prt Sc/SysRq - DS4 Share button
Pause/Break - moves you back to inserted disc in the main menu
Backspace - back
Enter- enter
Arrow keys - moving in menus
Matrix Blu-ray disc:
In-movie controls:
Esc - Pause/On-screen display
F1 - on-screen display (shows movie progress, type of audio track, etc)
F2 - BD pop-up menu
F3 - PS4 disc options (pop-up menu, subtitles, audio, etc)
Backspace - Pause/On-screen display
Up arrow - bring up BD pop-up menu
Down arrow - close BD pop-up menu
Right/left arrow - moving in menus
Enter - enter