USB / MX4SIO / iLink

USB mass storage, MX4SIO SD cards (via memory-card slot adapter), and iLink (SBP2 over IEEE 1394) are OPL's three BDM mass-device transports. They share the same filesystem rules, folder layout, and Game Sources controls — all three mount into the massN: namespace and are handled by the Block Device Manager (BDM).

i All three ship off — you opt in

On a fresh install RiptOPL ships with USB, iLink and MX4SIO all disabled and BDM Devices Start Mode set to Off — every device in Game Sources starts off so you enable exactly the hardware your rig has. Turn on the transport you use, and set a start mode, in Game Sources. Until you do, a fresh install boots to the start menu with no game-list tabs at all.

The three transports

USB

Standard USB mass storage (the usb BDM driver). The PS2's controller is USB 1.1, so a USB 2.0/3.x drive falls back to the console's slower bus speed; actual compatibility and throughput depend on the drive/enclosure. USB is substantially slower than the PS2 DVD drive, which is why some streaming-heavy games stutter even when the files are contiguous.

Enable toggle in Game Sources: USB → On/Off.

MX4SIO

The MX4SIO adapter plugs into the memory-card slot (SIO2 bus) and accepts a standard SD or microSD card. OPL registers it under the sdc / mx4sio BDM driver name. From OPL's perspective the card behaves identically to a USB drive — same folder layout, same filesystem requirements, same per-game settings — but it connects through the memory-card port rather than USB.

Enable toggle in Game Sources: MX4SIO → On/Off.

i MX4SIO and MMCE are different

MX4SIO mounts the SD card directly as a FAT32/exFAT block device (games in DVD/ and CD/ folders). MMCE (SD2PSX, MemCard PRO2) emulates a memory card and also carries an OPL game volume — they use different IOP drivers and separate enable toggles. See MMCE.

iLink (IEEE 1394 / FireWire)

iLink uses the SBP-2 protocol over the PS2's IEEE 1394 (FireWire) port. The BDM driver names for iLink devices are sd / ilink. Supported storage includes SBP-2 compliant hard drives and enclosures. This interface is only present on fat PS2 models that include the iLink port; slim PS2 models do not have an iLink port.

Enable toggle in Game Sources: iLink → On/Off.

⚠ Revision 2692 iLink launch status

On an SCPH-39001, the same IEEE 1394 disk listed and launched Ember in all four SDK flavours, but native OPL, Neutrino, and POPSTARTER failed at their reset/handoff boundaries. The post-2692 build corrects a confirmed Neutrino handoff mismatch by auto-emitting -qb with -bsd=ilink; hardware retest must still prove whether that was the complete cause. POPSTARTER's loose .ilink equip is present but unconfirmed, and native OPL remains under investigation. See the iLink isolation notes.

Supported filesystems

All three transports support FAT32 and exFAT, both on an MBR partition table. GPT is not supported for BDM mass devices (GPT is supported for the exFAT internal HDD — see Internal HDD).

Filesystem	Max file size	Max volume size	Notes
FAT32	4 GB − 1 byte	~2 TB	Games >4 GB require USBExtreme (.ul) split format
exFAT	Unlimited	Unlimited	Available since OPL v1.2.0 beta rev1880; MBR partition table

i exFAT allocation unit size

When formatting a drive as exFAT, leave Allocation unit size at the Default value in your format tool. Choosing a non-default cluster size can cause compatibility issues.

Folder layout

OPL expects the following directory structure at the root of the drive (or inside the optional BDM Prefix subfolder). OPL creates most of these folders for you the first time it initialises the device after you have enabled it in Game Sources — not on first boot, and never for a device you have not turned on. POPS/ is the exception: OPL never creates it, so make it yourself if you want PS1/VCD games.

DVD/        PS2 DVD5/DVD9 ISO and ZSO images (also supports >4 GB on exFAT)
CD/         PS2 CD-ROM ISO images (blue-bottom discs)
POPS/       PS1 VCD game images (*.VCD) — shown according to PS2/PS1 Game Display
CFG/        Per-game configuration files
ART/        Cover art images
VMC/        Virtual Memory Card images
THM/        Theme assets
LNG/        Language files
CHT/        PS2RD cheat files (.cht)
APPS/       Homebrew ELF files

i PS1 games on USB / MX4SIO / iLink

Put your *.VCD files in the POPS/ folder. PS2/PS1 Game Display can show separate PS2 / PS1 pages, a combined list, or one locked type; L3 is available only in Both (L3) and Mixed. See PS1 Games (VCD) for the full setup — you will also need POPSTARTER on the same device. For iLink, keep the loose usbd.irx.ilink + usbhdfsd.irx.ilink pair in that POPS/ folder; RiptOPL strips .ilink only when copying the pair to the memory card and launches with the normal mass:/POPS/XX.<game>.ELF selector.

Fragmentation

OPL's BDM driver supports up to 64 fragments per file (since OPL v1.2.0 beta rev1893). Games with more than 64 fragments will fail to load. Normal use rarely exceeds this limit, but drives that have been filled incrementally over a long time — especially FAT32 drives — can accumulate heavy fragmentation.

The recommended fix is simple and permanent:

Copy files off

Copy all game files and OPL folders from the drive to a folder on your PC.

Format the drive

Format the drive fresh (FAT32 or exFAT, MBR, default allocation unit size). Do not use a third-party defragmenter — they rearrange data on-disk but the PS2's IOP driver works at the block level and the results are unpredictable.

Copy files back in order

Copy your game files back one at a time, or in one sequential batch, rather than in parallel. Copying files sequentially ensures each file is laid down contiguously. You only need to redo this when fragmentation becomes a problem again.

USBExtreme format (.ul) for FAT32 and large games

FAT32 limits individual files to just under 4 GB. DVD9 games (dual-layer discs) are commonly 6–8 GB — larger than FAT32 can hold in a single file. The USBExtreme (also called USB Advance) format splits these games across multiple files named with a .ul-style scheme and an index file.

OPL reads both plain .ISO files and USBExtreme split sets from the DVD/ folder. If your drive is formatted exFAT you can use plain .ISO or .ZSO files for all games regardless of size. If your drive is FAT32, use USBExtreme for any game over ~4 GB.

Use OPLUtil or USBUtil on PC to split an ISO into USBExtreme format.
The split ul.* files and ul.cfg belong at the configured library prefix, not inside DVD/.
OPL detects USBExtreme sets automatically — no extra setting needed.
ZSO (compressed ISO) is also supported on both FAT32 and exFAT. See ZSO Format.

Enabling devices in Game Sources

Open Game Sources from the Settings Index for the start mode and the per-transport toggles. The cache and prefix rows are not on that screen: they are on General & System, so Game Sources is strictly device selection:

Setting	What it does	Default
BDM Devices Start Mode	Off / Manual / Auto — controls when OPL scans for mass devices (Game Sources)	Off
USB	Enable/disable the USB mass storage driver (Game Sources)	Off
iLink	Enable/disable the IEEE 1394 SBP-2 driver (Game Sources)	Off
MX4SIO	Enable/disable the MX4SIO SD driver (Game Sources)	Off
BDM Cache	Read-ahead cache size in sectors (0–32) — General & System	16
BDM Prefix Path	Optional subfolder inside the drive root where OPL looks for its folders — General & System	(empty)

i Start Mode: Off, Manual, Auto

Off is the shipped default — no mass-device tab is registered at all; leave it there if you have no mass devices attached and want the fastest possible boot. Manual registers the tab at boot but holds the scan until you navigate to it — the device is scanned on demand. Auto scans immediately on boot.

BDM Prefix

The BDM Prefix Path setting, on General & System, lets you store your OPL folder tree inside a subfolder of the drive rather than at the drive root. For example, setting the prefix to OPL tells RiptOPL to look for DVD/, CD/, CFG/, etc. inside mass0:/OPL/ rather than directly at mass0:/.

The same prefix applies to all BDM mass devices (USB, MX4SIO, iLink, exFAT HDD). Leave it empty to use the drive root, which is the most common setup.

With a prefix set, RiptOPL creates its folders inside the prefix, including every level of a nested one such as PS2/OPL, and leaves the drive root alone. Leading and trailing slashes are ignored, and backslashes are read as forward slashes.

Multiple devices at once

OPL can enumerate up to 8 BDM slots (mass0: through mass7:). Each connected device occupies one slot. If you have a USB drive in mass0: and an MX4SIO card in mass1:, both appear as separate game lists (with the slot number shown in the tab label). You do not need to configure them separately — one BDM Devices Start Mode and one BDM Prefix Path apply to all slots.

Common issues

Drive is not detected / game list is empty

Confirm the correct transport is enabled in Game Sources (USB / iLink / MX4SIO).
Check that BDM Devices Start Mode is not set to Off.
Make sure the drive uses an MBR partition table (not GPT) and is formatted FAT32 or exFAT.
Verify the folder structure — games must be in DVD/ or CD/ (case-sensitive). If you set a BDM Prefix, games must be under that subfolder.
Try re-seating the drive or adapter, then return to the game list and press Triangle → Refresh.

Game freezes or fails to load (fragmentation)

The 64-fragment limit is the most common cause of load failures on FAT32 drives that have been filled over time. Copy all files to PC, format the drive, and copy them back sequentially. See Fragmentation above.

FAT32 drive cannot hold a large game

DVD9 games over ~4 GB cannot be stored as a single ISO on FAT32. Use USBExtreme format (split via OPLUtil / USBUtil) or reformat the drive as exFAT and use plain ISO files.

MX4SIO not detected

MX4SIO uses the memory-card port. Make sure MX4SIO is enabled in Game Sources. Note that MX4SIO and a physical memory card (or MMCE device) cannot share the same slot simultaneously.

iLink not detected

iLink is only available on larger PS2 models. Slim PS2 (PS2 Slim / 7000x and later) do not have the iLink port. If your model has the port, make sure iLink is enabled in Game Sources and the drive is SBP-2 compliant.