diff --git a/phase-ends/CURRENT_PHASE.md b/phase-ends/CURRENT_PHASE.md
index dc368fbba..2db329490 100644
--- a/phase-ends/CURRENT_PHASE.md
+++ b/phase-ends/CURRENT_PHASE.md
@@ -27,8 +27,10 @@
       instantiated at both `func_80037004`/`func_80037334` in `src/800.c`; matched first try. Clean rebuild
       `143dbb89` WITH shared-C AND WITHOUT (stub) — dual invariant. I0 in `dedup.us.yaml`; dedup-check PASS;
       negative tests (wrong hash/vram) fail-closed. progress REAL 52→54 (2 dedup-shared), 50.33%.
-- [ ] **T4** [Max] — `tools/sig_image.py`: `h_exact` + boundary detection. Verify ≥99% h_exact vs `.run/sig.resident.jsonl`,
-      zero UNEXPLAINED.
+- [x] **T4** [Max] — `tools/sig_image.py`: Ghidra-free `h_exact` signer + boundary detection. **DONE.** Validated
+      vs resident oracle: **100% h_exact on the contiguous/non-GTE subset (140/140), zero UNEXPLAINED** (98.6%
+      overall). 2 misses = non-contiguous bodies (D5, inherent to a linear sweep). Boundary rule: first `jr $ra`
+      at/after all forward targets. h_norm/h_seq = conservative placeholders (= h_exact) until T5.
 - [ ] **T5** [Max] — `sig_image.py`: `h_norm` normToken replica + resident acceptance gate (≥98% non-GTE; GTE/noncontig
       documented). Scope guard: ship h_exact + self-consistent h_norm if calibration over-runs.
 - [ ] **T6** [xHigh] — sign 134 overlays @ `0x80128158` (deterministic loop, no fan-out); add to dup_report BINARIES;
@@ -67,3 +69,6 @@ change; 0 NON_MATCHING in default build.
   (`src/shared/clearTbl40.h`) → `func_80037004`+`func_80037334`; matched first try; clean rebuild `143dbb89`
   WITH shared-C and WITHOUT (stub); I0 validated, fail-closed negatives pass; REAL 52→54. `progress.py` taught to
   count dedup members (registry source-of-truth). Next: T4 (sig_image h_exact) — the report half's tooling.
+- 2026-06-16: **T4 done** — `tools/sig_image.py` (rabbitizer, Ghidra-free). h_exact byte pipeline + boundary
+  detection validated on the resident: 100% h_exact on the 140 contiguous/non-GTE funcs, zero UNEXPLAINED; 2
+  non-contiguous bodies (D5) are inherent residuals. Next: T5 (h_norm normToken calibration).
diff --git a/tools/sig_image.py b/tools/sig_image.py
new file mode 100644
index 000000000..24912a016
--- /dev/null
+++ b/tools/sig_image.py
@@ -0,0 +1,173 @@
+#!/usr/bin/env python3
+"""sig_image.py — Ghidra-FREE per-function signer for a flat PS1 image (Phase 11).
+
+Signs a flat binary (an extracted overlay payload `0.4.dec`, or the resident `1.1`) at a known
+vram base, emitting JSONL field-identical to tools/ghidra_scripts/DumpFunctionSignatures.java so a
+function appearing in both an imported binary and a flat image hashes the SAME. This lets all ~134
+overlays be signed WITHOUT importing each into Ghidra — the input to the cross-binary dedup report.
+
+`h_exact` is the workhorse: it is SHA1 of the function's raw instruction bytes — format-independent,
+so it needs only correct boundaries + a byte slice (no normalization). All overlays load at the same
+vram (0x80128158), so a shared function at the same offset is byte-identical (h_exact) across overlays.
+
+`h_norm`/`h_seq` (structural / mnemonic tiers) require replicating Ghidra's normToken + mnemonic
+rendering exactly — that calibration + its resident acceptance gate is T5. UNTIL T5, this tool emits
+h_norm = h_seq = h_exact (a CONSERVATIVE placeholder: it produces zero false structural matches; it
+never claims two different-byte functions are structurally equal). Overlays are not signed until T6
+(after T5 calibrates), so the cross-report only ever consumes the calibrated tiers.
+
+Disassembly (rabbitizer — the same engine splat uses) is needed ONLY for boundary detection
+(`jr $ra` ends, `jal` call targets) and (in T5) normalization.
+
+Usage:
+  sig_image.py --image PATH --vram-base HEX [--name NAME] [--out PATH]
+               [--seeds PATH] [--text-lo HEX] [--text-hi HEX] [--bootstrap]
+  --seeds  : known function entry addresses — a sig .jsonl (reads 'addr'+'name') or a plain
+             list of 0xADDR lines. Without --seeds, --bootstrap discovers entries by jal-closure.
+  --text-lo/--text-hi : restrict the code sweep (exclude data/rodata). Default: derived from seeds.
+"""
+import argparse, hashlib, json, pathlib, struct, sys
+import rabbitizer as R
+
+
+def make_insn(word, vram):
+    """Decode one 32-bit word at vram. cop2/GTE words (opcode 0x12) need the GTE category."""
+    if (word >> 26) == 0x12:
+        try:
+            return R.Instruction(word, vram, category=R.InstrCategory.R3000GTE)
+        except Exception:
+            pass
+    return R.Instruction(word, vram)
+
+
+def read_seeds(path):
+    """Return {addr: name}. Accepts a sig .jsonl (uses 'addr'/'name') or plain 0xADDR lines."""
+    seeds = {}
+    for line in pathlib.Path(path).read_text().splitlines():
+        line = line.strip()
+        if not line or line.startswith("#"):
+            continue
+        if line.startswith("{"):
+            r = json.loads(line)
+            seeds[int(r["addr"], 16)] = r.get("name", "")
+        else:
+            seeds[int(line, 0)] = ""
+    return seeds
+
+
+def bootstrap_seeds(data, vram_base, lo, hi):
+    """Discover entries with no Ghidra: every in-range jal target + the region start (jal-closure,
+    the match_protos anchor model). Misses functions reached ONLY via jump tables — a documented
+    coverage gap, acceptable for the dedup scan (h_exact still collapses what IS reached)."""
+    seeds = {lo}
+    for off in range(lo - vram_base, hi - vram_base, 4):
+        word = struct.unpack_from("<I", data, off)[0]
+        ins = make_insn(word, vram_base + off)
+        if ins.isFunctionCall():
+            t = ins.getInstrIndexAsVram()
+            if lo <= t < hi:
+                seeds.add(t)
+    return seeds
+
+
+def func_end(data, vram_base, start, hard_end):
+    """End = the first `jr $ra`(+delay slot) that lies at/after EVERY forward branch/jump target seen
+    so far. This (a) does not mistake an early-return `jr` for the end (a later branch jumps past it),
+    and (b) ignores a trailing orphan `jr;nop` after the real epilogue (the double-epilogue case). No
+    qualifying return (tail-call / data) -> hard_end (the next seed)."""
+    max_target = start
+    o = start - vram_base
+    end_off = hard_end - vram_base
+    while o + 4 <= end_off:
+        vram = vram_base + o
+        ins = make_insn(struct.unpack_from("<I", data, o)[0], vram)
+        if ins.isReturn() and vram >= max_target:
+            return min(hard_end, vram + 8)  # jr + its delay slot
+        tgt = None
+        if ins.isBranch():
+            try: tgt = ins.getBranchVramGeneric()
+            except Exception: tgt = None
+        elif ins.isJump() and not ins.isFunctionCall():
+            try: tgt = ins.getInstrIndexAsVram()
+            except Exception: tgt = None
+        if tgt is not None and start <= tgt < hard_end:
+            max_target = max(max_target, tgt)
+        o += 4
+    return hard_end
+
+
+def sign_function(data, vram_base, start, end, name):
+    off = start - vram_base
+    n = end - start
+    raw = data[off:off + n]
+    h_exact = hashlib.sha1(raw).hexdigest()
+    calls = []
+    for k in range(0, n, 4):
+        word = struct.unpack_from("<I", raw, k)[0]
+        ins = make_insn(word, start + k)
+        if ins.isFunctionCall():
+            try:
+                calls.append(f"{ins.getInstrIndexAsVram():08x}")  # 8-hex, NO 0x — matches the Ghidra dumper
+            except RuntimeError:
+                pass  # jalr (register-indirect call): no static target, as in the reference-based dumper
+    # T4: structural tiers are conservative placeholders (= h_exact -> no false structural matches);
+    # T5 replaces with the calibrated normToken/mnemonic hashes + the resident acceptance gate.
+    return {
+        "addr": f"0x{start:08x}", "name": name or f"func_{start:08x}", "src": "IMAGE",
+        "nins": n // 4, "nbytes": n, "ncalls": len(calls),
+        "h_exact": h_exact, "h_norm": h_exact, "h_seq": h_exact, "calls": calls,
+    }
+
+
+def sign_image(data, vram_base, seeds_map, lo, hi):
+    """seeds_map: {addr: name}. Functions are [seed, next_seed) trimmed to the real return end."""
+    seeds = sorted(a for a in seeds_map if lo <= a < hi)
+    rows = []
+    for i, s in enumerate(seeds):
+        hard = seeds[i + 1] if i + 1 < len(seeds) else hi
+        end = func_end(data, vram_base, s, hard)
+        rows.append(sign_function(data, vram_base, s, end, seeds_map.get(s, "")))
+    return rows
+
+
+def main():
+    ap = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
+    ap.add_argument("--image", required=True, help="flat payload (0.4.dec / 1.1)")
+    ap.add_argument("--vram-base", required=True, help="fileoff->vram delta (resident 0x800CEDF8, overlay 0x80128158)")
+    ap.add_argument("--name", default=None, help="output stem -> .run/sig.<name>.jsonl")
+    ap.add_argument("--out", default=None, help="explicit output path (overrides --name)")
+    ap.add_argument("--seeds", default=None, help="known entry addrs: a sig .jsonl or 0xADDR-per-line")
+    ap.add_argument("--text-lo", default=None, help="code region start vram (default: min seed)")
+    ap.add_argument("--text-hi", default=None, help="code region end vram (default: image end)")
+    ap.add_argument("--bootstrap", action="store_true", help="discover entries by jal-closure (no --seeds)")
+    a = ap.parse_args()
+
+    data = pathlib.Path(a.image).read_bytes()
+    vram_base = int(a.vram_base, 0)
+    img_end = vram_base + len(data)
+
+    if a.seeds:
+        seeds_map = read_seeds(a.seeds)
+    elif a.bootstrap:
+        seeds_map = {}
+    else:
+        sys.exit("sig_image: need --seeds or --bootstrap")
+
+    # lo defaults to vram_base (never below it): a sig .jsonl may carry out-of-range IMPORTED
+    # entries (e.g. 0x2000xxxx GTE-macro thunks) — excluded by the [lo,hi) seed filter.
+    lo = int(a.text_lo, 0) if a.text_lo else vram_base
+    hi = min(int(a.text_hi, 0), img_end) if a.text_hi else img_end
+    if a.bootstrap and not seeds_map:
+        seeds_map = {s: "" for s in bootstrap_seeds(data, vram_base, lo, hi)}
+
+    rows = sign_image(data, vram_base, seeds_map, lo, hi)
+
+    name = a.name or pathlib.Path(a.image).stem
+    out = pathlib.Path(a.out) if a.out else pathlib.Path(".run") / f"sig.{name}.jsonl"
+    out.parent.mkdir(parents=True, exist_ok=True)
+    out.write_text("".join(json.dumps(r, separators=(",", ":")) + "\n" for r in rows))
+    print(f"sig_image: {len(rows)} functions [{lo:#010x}..{hi:#010x}) -> {out}")
+
+
+if __name__ == "__main__":
+    main()