Last updated: September 2026
PS2 emulation has exactly one hard requirement and it trips up everyone: the BIOS. PCSX2 will not open a game without it, and neither will NetherSX2 or AetherSX2 on Android. There is no high-level substitute the way some PS1 cores have. You dump it from a real PlayStation 2, you point the emulator at it, and then the whole library opens up.
This guide is the PS2 half of my RetroArch BIOS reference. It covers what the dump actually contains, which file the emulator wants, where that file goes on every platform I use, and how to make the dump yourself with a memory card and a USB stick.
What a PS2 BIOS Dump Contains
A proper dump is not one file. The biosdrain homebrew writes a set:
| File | Size | What it is | Do you need it? |
|---|---|---|---|
SCPH-70012_BIOS_V12_USA_200.bin (name varies by console) | 4,194,304 bytes | The main BIOS (rom0) | Yes. This is the file the emulator loads. |
.rom1 | varies | DVD player firmware | Optional. Only for playing DVDs. |
.rom2 | varies | Chinese-region extras | Optional. Almost never present. |
.erom | varies | Encrypted DVD player component | Optional. |
.nvm | 1,024 bytes | Console settings (language, clock) | Optional. Gets created fresh if missing. |
.mec | 4 bytes | Mechacon version | Optional. |
The main .bin is always exactly 4 MB. If yours is a different size, it is not a complete dump. Filenames vary by dumper and by console, so do not rename anything; PCSX2 and NetherSX2 read the version and region from inside the file.
Which region and version
| Console model | Region | Common example |
|---|---|---|
| Model number ending in 2 | North America | SCPH-70012_BIOS_V12_USA_200.bin |
| Model number ending in 4 | Europe / PAL | SCPH-70004_BIOS_V12_EUR_200.bin |
| Model number ending in 0 | Japan | SCPH-70000_BIOS_V12_JAP_200.bin |
Any version works. Slim-era dumps (SCPH-70000 through SCPH-90000 series) are what most guides show, and PCSX2 has no preference between them. Region only matters for the boot logo language and the DVD player; games from any region run on any BIOS. I keep a USA dump and never think about it.
PCSX2 2.x (Windows, Linux, macOS, Steam Deck)
PCSX2 2.x replaced the old wxWidgets interface with Qt and moved the BIOS folder along with it.
| Platform | BIOS folder |
|---|---|
| Windows (installer) | %USERPROFILE%\Documents\PCSX2\bios\ |
| Windows (portable) | bios\ inside the PCSX2 folder |
| Linux (Flatpak, Steam Deck) | ~/.var/app/net.pcsx2.PCSX2/config/PCSX2/bios/ |
| Linux (AppImage) | ~/.config/PCSX2/bios/ |
| macOS | ~/Library/Application Support/PCSX2/bios/ |
The version-proof way to find it: open PCSX2, go to Settings > BIOS, and click Open BIOS Folder. Copy the .bin there, hit Refresh List, and the file appears with its region and version parsed out. Select it and close the dialog.
EmuDeck users on Steam Deck: EmuDeck sets the folder to Emulation/bios/ on whichever drive you picked, and the built-in BIOS checker in the EmuDeck app tells you if the PS2 file is missing.
Two settings I change right after the BIOS loads:
- Settings > BIOS > Fast Boot: on. Skips the PS2 logo and goes straight to the game.
- Settings > Emulation > Enable Cheats: off until you actually add a
.pnachfile, because it slows loading for nothing.
NetherSX2 and AetherSX2 (Android)
Both emulators run a first-launch wizard that asks for two folders: one for the BIOS, one for games.
- Put the BIOS
.binon the device. I useEmulation/bios/on the SD card and share it with every emulator, same as on PC. - Open the app. On first launch the wizard stops at the BIOS step. Tap Add, browse to the folder, and pick the file.
- If you skipped the wizard, it is at Settings > System > BIOS Directory, then tap the file to select it.
NetherSX2 reads plain .bin files. It does not read .zip archives and it does not search subfolders. AetherSX2’s final open build behaves the same way. If the file list stays empty after you point it at the folder, the app was denied storage permission; go to Android Settings > Apps > NetherSX2 > Permissions and allow “All files access”.
The current NetherSX2 build is the Classic release maintained on GitHub after the original patch project, and it is the one I install on every Android handheld. My full walkthrough, including renderer and speedhack settings, is in the NetherSX2 setup guide.
RetroArch (PCSX2 and Play! cores)
The libretro PCSX2 core is years behind standalone and I do not recommend it, but if you use it, the BIOS goes in the RetroArch system directory under a pcsx2/bios/ subfolder. The Play! core is a HLE emulator that needs no BIOS, and its compatibility reflects that.
How to Dump Your PS2 BIOS
You need three things: a PlayStation 2 (fat or slim, any region), a FreeMcBoot memory card, and a FAT32 USB stick.
- Get FreeMcBoot on a memory card. The easiest route is buying a card that ships with it preinstalled. If you already have a PS2 with FreeMcBoot, you can install it to a blank card from the FreeMcBoot installer.
- Download biosdrain. It is open-source, on GitHub. Grab the
.elfand put it on the USB stick. - Boot the PS2 with the FreeMcBoot card in slot 1. From the FreeMcBoot menu open uLaunchELF (usually listed as wLaunchELF).
- Navigate to
mass:/and runbiosdrain.elf. It reads every ROM region and writes the file set to the USB stick. Takes under a minute. - Copy the files to your PC and check the main
.binis 4,194,304 bytes.
That dump is yours for life. Back it up somewhere that is not the same SD card as your ROMs, because SD cards die.
Slim consoles made after 2008 (the SCPH-90000 series) resist FreeMcBoot on the card alone and need a FreeDVDBoot disc to launch it. Fat consoles and earlier slims boot it directly.
Common Problems
“No BIOS found” or an empty BIOS list. Wrong folder, a subfolder, or a storage permission on Android. PCSX2’s Open BIOS Folder button removes the guesswork.
PCSX2 lists the BIOS but games hang at the logo. Turn Fast Boot off once to let the BIOS initialise its settings, then back on. Also confirm the dump is 4 MB; truncated dumps get this far and no further.
Wrong language on boot. The .nvm file from your dump carries the console’s language setting. Delete the .nvm next to the BIOS and PCSX2 regenerates it with defaults, or change it under Settings > BIOS.
NetherSX2 runs slow after the BIOS loads. That is not a BIOS issue. See the renderer and resolution settings in the setup guide; the BIOS has no effect on speed.
Why No Download Links
The BIOS is Sony’s copyrighted firmware. Dumping your own console is the defensible position, it takes ten minutes with a $15 memory card, and it produces a file you can trust. The “PS2 BIOS pack” sites are ad farms and I will not send you to one.
FAQ
Which PS2 BIOS is best for PCSX2?
Any complete dump works. Most people end up with a slim SCPH-70000 or SCPH-77000 series dump in their own region. PCSX2 has no performance difference between versions.
Does NetherSX2 need a BIOS?
Yes. NetherSX2 and AetherSX2 both require a real PS2 BIOS file and will not start a game without one.
Can I use a PS2 BIOS for PS1 games?
In DuckStation, yes: the PS2 firmware contains the PS1 boot ROM and DuckStation reads it. RetroArch cores want the separate PS1 files; see the PS1 BIOS guide.
Do I need rom1, rom2 and erom?
Only if you want the DVD player. Games load with the main .bin alone.
Does the BIOS region have to match the game?
No. Any region BIOS runs games from any region on PCSX2 and NetherSX2.
PCSX2 | PCSX2 BIOS dumping docs | biosdrain on GitHub
Last verified: September 2026