ePSXe’s “missing BIOS” warning means the emulator cannot find — or cannot use — a PlayStation BIOS file. Unlike some emulators, ePSXe does not bundle one, and neither do we: the BIOS is Sony’s copyrighted firmware. Here is how to clear the error the legitimate way.
Why ePSXe asks for a BIOS at all
The BIOS is the console’s built-in firmware. ePSXe emulates the hardware around it, but most games call BIOS routines to boot, read discs and manage memory cards. The readme in the official ePSXe package states the legal position in one line: you may only be in possession of the copyrighted BIOS if you are legally entitled to do so — in practice, you dumped it from a console you own.
Fix it in three steps
- Have a BIOS file. If you don’t, that is the whole problem. Our legal BIOS guide explains how to dump firmware from your own PS1 (and why download sites are not a shortcut — their files can’t be verified, and the checksums advertised for them don’t match the genuine article).
- Put it in the bios folder. Inside your ePSXe directory there is a bios folder; your .bin belongs there. (The folder ships with an erase.me placeholder — that’s normal.)
- Select it. Config > BIOS, choose the file, save, and restart ePSXe. On Android: Preferences > BIOS, and make sure the file sits in a folder the app is allowed to see (scoped storage).
“It’s selected but the error stays”
- Wrong file: a 0-byte or misnamed dump, or a file that isn’t a BIOS at all. Re-dump or re-copy it.
- Region games vs BIOS region: some titles are picky; a BIOS from your own console of the same region as your discs is the cleanest pairing.
- HLE fallback confusion: ePSXe can attempt HLE BIOS emulation for some games (v2.0.18 improved HLE for specific titles), but HLE is partial — games that need a real BIOS will keep complaining or boot to the black screen.
Once the BIOS is selected properly, the warning disappears for good — it is a configuration state, not a recurring fault.