biosdrain PS2 BIOS Dumper: ELF Download, ISO & Screen Guide

What You Need Before the BIOS Dump

There are four things to get ready before you start, and none of them needs soldering:

• A PlayStation 2 that you own, fat or slim. The model code on its label (SCPH-…) will appear in the BIOS file names later.
• A way to start homebrew. The PCSX2 docs recommend either a FreeMcBoot card in a memory slot or a burned FreeDVDBoot disc. Both are softmods: they live on a card or a DVD and leave the hardware alone.
• A USB flash drive, ideally a USB 2.0 one, formatted as FAT32 with an MBR partition table. Formatting wipes it, so back up anything on it first.
• A computer (PC or Mac) to format the stick and receive the BIOS.

Which homebrew route suits your unit? This summary follows the official table, and this guide uses the first or the third route:

Step 1: Download biosdrain and Prepare the USB Stick

Download biosdrain.elf from the official GitHub releases page using the button above; this ELF is the whole program. That page is the only place the author publishes it; the file is the program the console will launch, not an installer for your PC. Do not rename it. The author also asks politely that you never share the BIOS you produce.

Next, format the stick. This is the one step where you can lose data, so check the device name twice. The PCSX2 documentation suggests these tools:

• On a PC: Rufus (the portable version is fine). Pick the right device, set Boot selection to Non bootable, Partition scheme to MBR, File system to FAT32 or Large FAT32, then Start.
• On a Mac: Disk Utility. Choose View, then Show All Devices, select the stick, click Erase and use MS-DOS (FAT) with the Master Boot Record scheme.
• On Linux: GNOME Disks or KDE Partition Manager. Create an MBR/DOS partition table with one FAT32 partition.

Put biosdrain.elf in the top level of the stick and eject it safely. The biosdrain readme adds two tips: exFAT also works on its side, and if the console still ignores a large stick, make one small 1 GB partition and leave the rest unformatted.

Step 2: Start Homebrew on Your PS2

Both recommended routes end in the same place: uLaunchELF, a small file manager that can open USB sticks, memory cards and discs and start programs from them. Newer FreeMcBoot cards such as 1.966 may ship wLaunchELF instead; it works the same way.

With a FreeMcBoot Card

1. Insert the card in memory card slot 1.
2. Leave the disc tray empty and switch the console on.
3. When the FreeMcBoot menu appears, select uLaunchELF.

With a FreeDVDBoot Disc

1. Grab the ISO made for your exact model from the FreeDVDBoot repository on GitHub. All slim models share one English ISO; fat units need the ISO that matches their DVD player version.
2. Burn it to a DVD-R at the lowest speed your burner offers (4x or slower) and finalise the disc.
3. Boot with no disc, press Circle to open System Configuration and change the language to English. The exploit fails in other languages.
4. Insert the disc and wait. uLaunchELF should open within a few seconds. On a slim, press the lid down firmly if the disc does not spin.

The newest SCPH-900xx consoles with a date code later than 8B generally reject Free McBoot (FreeMcBoot). Use FreeDVDBoot or a Fortuna/OpenTuna card on those.

Step 3: Run biosdrain and Wait for the Screen

Plug the stick into one of the front ports. In uLaunchELF, open FileBrowser, enter mass: and select biosdrain.elf; Circle normally confirms. The tool detects the stick by itself and starts writing straight away.

Now be patient. The PS2’s USB link is slow, and the screen shows each BIOS part as it is read and saved to your USB drive. Do not turn the console off or pull the stick while it works. When the last line on screen reads “Finished Everything”, the job is done: switch off, remove the stick and plug it into your PC.

Owners with a network adapter can skip USB, which is the other method biosdrain supports. With ps2link running on the PS2, run “ps2client execee host:biosdrain.elf” from a terminal opened where the file sits, and biosdrain writes the BIOS parts to the host root instead of a stick.

Check the Output Parts and SCPH Model

Open the stick on your PC. Every BIOS file starts with your console’s model code and ends in a different extension. The exact set depends on the hardware revision:

• .rom0: the main image, exactly 4,194,304 bytes (4 MB). This is the BIOS emulators load.
• .rom1 and .rom2: DVD-player code and, on Asian models, font tables. biosdrain fixes ROM1 at 4096 KB.
• .erom: encrypted DVD-player code on later units.
• .nvm: the small settings area (language, clock, display options).
• .mec: the mechanical controller version.

Keep the whole BIOS set together, unchanged and unzipped. Older dumpers wrote one combined .bin instead; that still works, but biosdrain’s split output is what PCSX2 and ARMSX2 expect today.

To confirm the BIOS is perfect, hash the main part and compare it with the Redump DAT for PlayStation 2 BIOS images. PowerShell: Get-FileHash with -Algorithm SHA1. Mac Terminal: shasum. Linux: sha1sum. A match means a perfect BIOS; no match usually means an active modchip interfered, so switch it off and run the tool again.

BIOS Extraction Problems and Fixes

• mass: is empty in uLaunchELF: the stick is not compatible. Try another one, preferably USB 2.0, and confirm it is MBR plus FAT32, not GPT, exFAT or NTFS.
• The tool seems frozen: wait several minutes. USB writes on this hardware are slow, and pulling the stick early leaves broken parts.
• Main part is smaller than 4 MB: the copy stopped early. Repeat the dump with the PS2 left alone until the final message.
• The disc shows as a game disc, not DVD Video: a modchip is intercepting the drive. FreeDVDBoot is not needed on a chipped console; use the chip to install FreeMcBoot, then disable the chip before you launch biosdrain.
• FreeDVDBoot does nothing: check the PS2 language is English, the disc is a finalised DVD-R burned slowly, and the ISO matches your model.
• PCSX2 or ARMSX2 rejects the files: make sure they are not zipped, keep the original names and remove odd characters from the path.

Which Consoles the Tool Covers

biosdrain is not tied to one market. It reads whatever BIOS the hardware carries, so the same ELF works on a Japanese SCPH-10000 launch unit, a US slim, a PAL fat model from Europe or a late Chinese console. The only limit is the homebrew route: if FreeMcBoot, Fortuna or FreeDVDBoot starts on your unit, biosdrain will too. Asian models write a larger .rom1 because it also holds font tables, and some early units have no .erom at all, so do not worry if your list looks shorter than a friend’s.

Devkits, the PSX DVR combo and Bravia TVs with a built-in PS2 are edge cases. FreeDVDBoot lists the Bravia TV units as supported, but check the community notes for your exact hardware before you start.

Where the Files End Up and How to Store Them

After the copy, the root of the stick holds every BIOS part plus nothing else from biosdrain. Move the set to your PC straight away and make two backups: one on another drive and one in private cloud storage that only you can open. Rename nothing. Emulators read the model and the version from inside the BIOS, but they find the parts by name, and the .nvm and .rom1 parts are matched to the main BIOS by the shared prefix.

If you own several consoles, keep each BIOS set in its own subfolder named after the model. That way an American, a Japanese and a European BIOS sit side by side and you can tell them apart months later. A short text note with the SHA1 of each main file helps too: if a copy ever gets damaged, you will know at once.

• Main BIOS (.rom0) plus all companion parts, in one place.
• A note with the model, the date of the copy and the SHA1.
• Nothing zipped while you use it; zip only for long-term storage.

This matters more than it sounds. A clean BIOS set is what lets PCSX2, ARMSX2 and RetroArch start your games without errors, and it is the first thing their support channels ask about when something goes wrong.

Using the Copy in Emulators

On a PC, copy the BIOS parts into the bios folder of PCSX2 or point the app at the place where you keep them; our PCSX2 BIOS setup walkthrough covers the wizard, the paths and the list. On Android, ARMSX2 imports the main BIOS on its first launch and keeps its own private copy. RetroArch’s PlayStation 2 core reads it from the system directory set in its options.

Because the BIOS comes from your own hardware, it already matches the games you bought with it: a US unit gives you an NTSC-U image for American games, and a European or Japanese unit gives you the right one for those markets; the region table in our PS2 BIOS overview shows which model code belongs where. If you collect imports from other regions, copy each console you own; the emulators let you keep several side by side and pick one per game.

After the Copy: Quick Checklist

Run through this list once the stick is back on your PC. It takes two minutes and saves hours of guessing later:

• The main .rom0 is exactly 4 MB and its SHA1 matches a Redump entry for your model.
• The companion parts sit next to it with the same prefix.
• Two backups exist outside the app folders.
• The softmod card or disc is stored safely in case you want to dump another unit later.

Then open PCSX2 or ARMSX2 and add the BIOS. PCSX2 lists it with its market (USA, Japan and so on) and version, and ARMSX2 shows the same details after import. If both apps recognise it, the dumping process is complete and you can start playing the games you own. Treat this page as your installation guide for the hardware side; the software side is covered on the PCSX2 page linked above.

One last tip on BIOS extraction from rare units: if you own a Japanese launch console or a 50 Hz fat model with an unusual revision, its BIOS may not appear in every hash list yet. Note the model and SHA1 and compare again later; a dump that loads and runs games normally is almost always fine.

Why BIOS Dumping Beats a Random Copy

Search results are full of zipped packs and re-uploads that claim to be a full PlayStation BIOS collection. Some are incomplete, some carry altered files, and none of them come with a way to prove what is inside. Your own BIOS can be checked against Redump in seconds, it never disappears from a file host, and it is the route the emulator teams document. The BIOS is Sony’s copyrighted software, so taking somebody else’s copy is not allowed in most countries; making a backup of a unit you own is the accepted path. Laws differ, so check yours.

There is also a practical side: once the BIOS files are on your PC, store them in two places. You will never need the PS2, the stick or the softmod again for emulation, and every future install takes seconds.