Phantasy Star Generation 2 — Save State Editor

A Windows Forms (.NET 10) editor for PCSX2 save states (.p2s) of Phantasy Star Generation:2 (the PS2 remake of Phantasy Star II; Japanese release SLPM-625.53).

It edits Meseta and each character's level, HP, TP, attributes (Attack, Defense, Stamina, Intellect, Agility, Luck, Skill) and Experience, and displays each character's equipment and the shared item list. It always writes a new *_edited.p2s file — your original is never modified.

Usage

1. File ▸ Open… and pick your PhantasyStarGeneration2.p2s.
2. Edit Meseta at the top; pick a character to edit their stats/experience.
3. File ▸ Save As… → writes a new *_edited.p2s.
4. Load the edited state in PCSX2.

The character list shows all eight roster members. The two recruited members (Eusis, Nei) are marked “● in party”; the rest are “○ reserve” — they exist in the save pre-seeded at Lv1 and are editable, but aren't in your party yet.

How it works

.p2s files are ZIP containers whose regions use Zstandard (ZIP method 93). The game's PS2 RAM lives in the eeMemory.bin entry. SaveFormat/P2SArchive.cs parses the container manually, decompresses with ZstdSharp, and repacks — reusing untouched entries verbatim and recompressing only eeMemory.bin.

Verified memory map (eeMemory.bin)

Anchored empirically against known in-game values. All character fields are u32 little-endian.

• Character array: base 0x247700, stride 0x84 (132 bytes), 8 slots in roster order: Eusis, Nei, Rudo, Amy, Hugh, Anna, Kain, Shir.
• Per-record offsets: +0x00 Level, +0x04/+0x08 HP cur/max, +0x0C/+0x10 TP cur/max, +0x14 Attack, +0x18 Defense, +0x1C Stamina, +0x20 Intellect, +0x24 Agility, +0x28 Luck, +0x2C Skill, +0x54 Experience.
• “Recruited” flag: the block at +0x30 is non-zero only for active party members.
• Meseta: lone u32 at absolute 0x248314.
• Inventory: array at absolute 0x247B14, stride 4, each entry [id u16][flags u16], ending at the first empty entry. Holds every owned item (equipped and bag). An item is equipped iff (flags & 0x3F) != 0x3F; then owner = flags & 0x3F (character index) and slot = (flags >> 6) & 7 (0 Head, 1 Body, 2 R.Hand, 3 L.Hand, 4 Feet). Confirmed item IDs so far: 1 Knife, 53 Steel Claw, 66 Ribbon, 82 Carbon Suit, 83 Carbon Vest, 128 Leather Shoes, 129 Espadrilles, 138 Monomate.

Offsets are overridable at runtime via a psg2_layout.json placed next to the executable.

Verified end-to-end

Editing Meseta and stats (e.g. Experience) was confirmed to take effect in PCSX2. Equipment and inventory were mapped from a controlled menus-closed save diff (buy one item + unequip two weapons) and decode exactly.

Still display-only / not yet mapped

• Equipment & items are read-only for now (display only); editing them is a possible extension.
• The complete item-ID → name table is unknown — unmapped IDs render as Item #N. You can name items yourself by editing psg2_items.json next to the exe (a simple { "id": "Name" } map); your entries override/extend the built-in table, no rebuild needed.
• The Job field is shown from a known table (only Eusis = Agent, Nei = — confirmed), not read from the save.

Note on TP / Attack: Eusis's stored TP reads 18 (you may see 10 in a menu — likely current vs. max), and the stored Attack is a base value the game adds the weapon bonus to (Nei stores 11, displays 16 with Steel Claws). Stamina/Intellect/Agility/Luck/Skill/Defense/Level/HP/Exp match the in-game numbers exactly.

Project layout

• SaveFormat/P2SArchive.cs — .p2s (zip + zstd) reader/writer.
• Game/Psg2Layout.cs — offsets, field defs, roster (JSON-overridable).
• Game/Psg2Character.cs, Game/Psg2Save.cs — read/write model.
• MainForm.* — UI (designer pattern: static layout in .Designer.cs, theme/behaviour in .cs).
• Analyzer/ — a separate console project used for offset reverse-engineering and round-trip tests (excluded from the app build).