Network Boot (SMB / UDP)

UDPFS and UDPBD stream PS2 games from a PC. They launch through Neutrino by default; UDPBD and UDPFS games (Files and IMG) can also run on OPL's own core, per game. Set Network Connectivity (Off / Manual / Auto) in Game Sources and choose the Protocol indented under it (the same row is on the Network page). The picker contains SMB / UDPFS / UDPBD / HTTP. SMB and HTTP use OPL's own core; HTTP has separate setup and limits.

The Network rows

Game Sources holds Network Connectivity with Protocol indented under it. Network holds the same Protocol row, plus SMB Version and Access. SMB Version (SMBv1 / SMB2) is editable for SMB. Access is Files/IMG for UDPFS, locked to Files for SMB/HTTP and IMG for UDPBD. The first protocol can start while the NIC is unused; switching an already loaded protocol requires restarting RiptOPL.

UDPFS is the one modern network-boot protocol (Rick Gaiser's UDPRDMA transport). It comes in two shapes, chosen with the Access row (see the comparison below): Files (the udpfs_ioman filesystem, loose ISOs) or IMG (the udpfs_bd block device, a served disk image). It has no DHCP client and needs a static PS2 IP; if neutrino.elf is missing at launch, OPL warns and returns to the menu.

SMB Version

When Protocol = SMB, the SMB Version row selects the dialect OPL's core speaks: SMBv1 (the default) or SMB2 (SMB 2.0.2 or 2.1). It applies to both halves of SMB, browsing the share from the menu and reading the game in game. The row is greyed unless Protocol is SMB, and its value is kept while greyed. SMB 3.x is not offered on OPL's core. The server must speak the dialect you pick: an SMBv1-only server lists nothing under SMB2, and an SMB2/3-only server lists nothing under SMBv1. A game on the Neutrino core does not use this row: Neutrino logs in with its own SMB 3.0 client on TCP 445 (see SMB through Neutrino).

Switching protocols with saved settings

UDPFS remembers its own Files/IMG choice independently of UDPBD, which always uses IMG. Switching to UDPBD and back should restore your previous UDPFS choice; a fresh configuration defaults to Files. Set Access on the Network page and make sure the PC server serves the matching folder or disk image.

Once a network driver has loaded, changing its protocol or UDPFS Access requires a restart. If restarting the application leaves the old connection active or the new protocol unavailable, fully restart the console and relaunch RiptOPL with the saved settings. Deleting your configuration is not the normal way to apply a protocol change. For a report, record both the old and new protocol, UDPFS Access, whether you restarted the application or console, and the server version.

Access — Files vs IMG

The Access row is on Settings → Network, alongside Protocol. Game Sources shows Connectivity and Protocol, but no Access row. Access is only free to change while Protocol = UDPFS — under SMB it is value-locked to Files and under UDPBD to IMG, greyed in both cases. Its two values are Files (default) and IMG. They are the same UDPFS protocol in two shapes: Files is the udpfs_ioman filesystem (udpfs:), IMG is the udpfs_bd block device (massN:).

Both ride the same UDPRDMA transport and the same server — pcm720/udpfsd, a single prebuilt Go binary (no Python) that serves both; just pass -fsroot <dir> for Files (the filesystem) or -bdpath <image> for IMG (the block image).

No PC on the network? udpfs-server by YouKnow-sys is an Android app that serves the same thing from a phone or tablet — folders or disk images, so it covers both Files and IMG. It is found by broadcast, so there is no server address to type in on the console, and it works over a router or a direct cable. Built on the same udpfsd underneath; MIT licensed.

Whichever server you use, a UDPBD-only udpbd-server (SUDPBDv2) will not talk to either backend. Because both backends bind the same UDPRDMA port and the IOP can load only one per boot, you can't run both at once — Files vs IMG is a config-time choice, and switching between them needs an OPL restart to take effect (OPL shows the usual restart-to-apply notice).

• Files launches with the stock -bsd=udpfs, which loads Neutrino's shipped bsd-udpfs.toml (the FHI filesystem driver, udpfs_ioman / udpfs_fhi). Neutrino opens the game by name (-dvd=udpfs:<name>) — no massN: block device, no fragment list. On the nightly Neutrino the -bsd is auto-detected.
• IMG launches with -bsd=udpfsbd, a RiptOPL-private token: Neutrino ships udpfs_bd.irx but no stock -bsd for it, so RiptOPL auto-places config/bsd-udpfsbd.toml into the bundled Neutrino folder. The private name is deliberate — it avoids colliding with stock's bsd-udpfs.toml (a different driver), so the block config and the stock filesystem config coexist on one install.

Requirements

• Static PS2 IP address (UDPFS and UDPBD). Their IOP modules (UDPFS in both Files and IMG) have no DHCP client — they read the static IP fields in Settings → Network and use them directly. While either is the Protocol, RiptOPL locks IP Address Type to Static and enables those fields; your DHCP choice is kept as the SMB/HTTP preference and comes back when you switch protocol. If DHCP is that kept preference, RiptOPL says so when you select a UDP protocol and again as a boot notice. (SMB can use DHCP or a static IP; it keeps its own address/port/share/credentials fields on the Network page, hidden automatically when either UDP protocol is selected.)
• PC-side UDPFS server running on the same LAN, matching the Access mode you chose. RiptOPL does not embed one. Open the package's PS2-Servers.url shortcut or visit PS2 Servers for the maintained UDPFS / SMBv1 / UDPBD all-in-one launcher. Advanced users can run pcm720/udpfsd directly. The standalone udpbd-server (SUDPBDv2) does not work with UDPFS — it belongs to the separate Protocol = UDPBD choice.
• Neutrino ELF for UDPFS. UDPFS Files and IMG launch via Neutrino by default and fall back to OPL's own core without it (see Which core runs a network game). The UDPFS feature ships its own bundled Neutrino (a ready-to-use neutrino/ folder in the release zip, pre-populated with the UDPFS config). See Neutrino Core. (SMB needs no Neutrino — it uses OPL's own core.)
• UDPFS runtime IP: RiptOPL rewrites the active Neutrino TOML's ip= value from the configured PS2 static IP before launch. Files uses config/bsd-udpfs.toml; IMG uses config/bsd-udpfsbd.toml. Keep that configuration writable and retain its expected IP token. A missing or unreadable required TOML aborts before teardown. A restructured, oversized or unwritable file is logged and left under the existing manual-IP contract; verify its IP yourself in that case.
• Game files laid out with standard OPL folders for the IMG mode and SMB: CD/, DVD/, ART/, CFG/, etc. — the same structure you would use on a USB drive. UDPFS Files also expects the standard layout: its served directory must contain CD/ and DVD/ subfolders (OPL lists from <served>/CD + <served>/DVD, never loose ISOs at the served root); drop an ISO into CD/ or DVD/ and the game appears.

Selecting a network protocol

# UDPFS Files — a folder with CD/ and DVD/ subfolders of ISOs
udpfsd -fsroot /path/to/games            # Files   (Linux/macOS)
udpfsd.exe -fsroot C:\path\to\games      # Files   (Windows)

# UDPFS IMG — a served FAT/exFAT disk image
udpfsd -bdpath /path/to/games.img        # IMG   (Linux/macOS)
udpfsd.exe -bdpath C:\path\to\games.img  # IMG   (Windows)

Which core runs a network game

UDPBD and UDPFS (Files and IMG) launch via Neutrino by default, even when the global Default Loader Core is <OPL>. Set a game's Loader Core to <OPL> to run it on OPL's own core instead (ported from YAOPL). The selector stays open, and its Default entry means Neutrino on these tabs. If the Neutrino launch cannot start (no neutrino.elf, a .zso image, too many fragments), the game falls back to the OPL core; a missing or unwritable bsd toml still returns to the menu with its message.

On the OPL core the game keeps the network: after the IOP reset OPL reloads the same block driver the menu used, gives it the static PS2 IP from Settings → Network, and fakes the game's own DEV9 and SMAP modules. There is no RetroAchievements telemetry and no in-game UDPTTY on that path. UDPBD reads at most 16 KiB per request. If the block driver does not start, the screen blinks red and the console stops instead of hanging on black. Not tested on hardware yet.

UDPFS Files on the OPL core (RiptOPL #161, Open-PS2-Loader #1134) follows Neutrino's own design. The menu opens the game's ISO on the server and keeps it open across the IOP reset; in game OPL loads udpfs_smap, udpfs_ministack and udpfs_fhi, which finds the server again and reads that open file. The game waits up to 30 seconds for the server at start and retries a read after a dropped connection. VMCs work and save to the server: each card is opened read-write and kept open the same way, and a card the server will not open for writing (read-only share, file already open) offers the usual prompt to continue without it. If the PC server is restarted while a game runs, the game cannot reopen its files; restart the game (Neutrino has the same limit). Not tested on hardware yet.

SMB is different: it is served by OPL's own core, needs no Neutrino, and behaves like the classic OPL network share. See SMB (network share).

One NIC, one transport — how the four rows interlock

The PS2 has a single Ethernet adapter (SMAP), and every network transport — SMB, UDPFS and UDPBD — loads a SMAP driver on it. Only one can own the adapter at a time, so RiptOPL exposes them as mutually exclusive values of one Protocol row rather than independent toggles. That replaces the old model, where a separate Network Boot toggle and an Ethernet (SMB) mode had to be greyed against each other. Network Connectivity decides whether the stack starts at all, and on the Network page the chosen protocol qualifies its own sub-rows (SMB Version is live only under SMB; Access is free only under UDPFS, and is value-locked to Files under SMB and to IMG under UDPBD). Switching between SMB, UDPFS and UDPBD is just changing the Protocol value and saving. (The same one-transport-per-boot rule is why Access = Files vs IMG is a config-time choice, applied on the next restart.)

Local devices — USB, MX4SIO, iLink, internal HDD (APA / exFAT), and MMCE — are entirely independent of these rows and browse alongside whichever network protocol you pick (or none).

Config file keys

These values are stored in settings_riptopl.cfg.

There is no separate config key for the Access (Files / IMG) row — it is folded into network_protocol itself (2 = Files, 3 = IMG). RiptOPL writes the legacy enable_udpbd / net_boot_protocol / eth_mode keys alongside the new one (a dual-write) purely so older builds can still read the config; network_protocol is the source of truth. The PS2 IP address used by the UDPFS IOP modules is read from the standard Network page fields (the same ones SMB uses); there are no protocol-specific network keys.

Game folder layout on the server

For the IMG mode (Access = IMG) and SMB, the PC server exports a FAT/exFAT volume the PS2 reads with the same folder conventions as a USB drive:

mass0:/  (device root — folders sit here directly by default)
  CD/          ← PS2 CD-ROM images (.iso)
  DVD/         ← PS2 DVD images (.iso)
  ART/         ← cover art (same naming as USB)
  CFG/         ← per-game config files
  VMC/         ← virtual memory cards (optional)
  POPS/        ← POPSTARTER.ELF and VCDs (UDPFS Files only; see PS1 setup)
  EMBER/       ← Ember runtime and games (where supported)
  APPS/        ← homebrew ELF files (optional)

The UDPFS Files mode uses the same CD/ + DVD/ layout, just without a disk image: point udpfsd -fsroot at a folder that contains CD/ and DVD/ subfolders of ISOs (OPL lists from <served>/CD + <served>/DVD, not the served root). Drop an ISO into CD/ or DVD/ and it appears in the UDPFS games list — no massN:, no fragment list, and server-dependent virtual ISO exposure (see the format limits below).

Troubleshooting

For further reading see Neutrino Core (per-game settings, launch args) and SMB (network share) (the SMB protocol in depth, which uses the OPL built-in core and does not require Neutrino).