I have had this problem ever since I upgraded to Lollipop myself.
My bios files have been upper and lower case, I have copied all of my bios files into every known directory to test any flaw including on my SD Card and system memory.
PCSX has failed on all attempts and I haven’t been able to even use it at all since the update.
Unfortunately, this lead me to replace most of my PS1 collection with PSP ports or remakes due to the poor amount of working PS1 emulators on Android.
I have tested PCSX Rearmed and Mednafen’s PS1 cores both on my SD Card and System Memory in plenty of folders to ensure nothing went wrong.
Funny fact is, these bios files were the same ones used in previous versions of RetroArch that worked flawlessly and allowed me to play Akumajou / Castlevania, Parasite Eve and many others before I updated to Lollipop.
I never modified anything after updating on RetroArch and it still failed.
I’m not sure if I ever updated RetroArch as soon as I updated to Lollipop, but it didn’t work once I updated.
The Google Play Store has ClassicBoy in which I found has a PS1 emulator, the same one RetroArch has unless otherwise noted and I tested loading Metal Gear Solid (Japan) and it worked without any modifications required.
The bios file ClassicBoy uses that works for me is the same one RetroArch should be using so I know it is fine and works. I’ve struggled with this problem just after updating to Lollipop and even tested and confirmed ClassicBoy which uses the same emulator works, please don’t blame people for failing to launch any PS1 games due to the wrong directory.
It worked before I even updated to Lollipop as well.
I have the Samsung Galaxy Note 4 with S-Pen. Try to reproduce these problems instead of blaming others, it’s all over the web.