diff --git a/config/regions.tsv b/config/regions.tsv
index 84a5fbd..c846d8d 100644
--- a/config/regions.tsv
+++ b/config/regions.tsv
@@ -128,6 +128,7 @@
 0x800301FC	0x8003022C	src/func_800301FC.c
 0x80030284	0x800302DC	src/func_80030284.c
 0x80030358	0x80030390	src/func_80030358.c
+0x800308C4	0x800309CC	src/func_800308C4.c
 0x80031F2C	0x80031F78	src/func_80031F2C.c
 0x80031F78	0x80031FC4	src/func_80031F78.c
 0x800321EC	0x800321F8	src/func_800321EC.c
diff --git a/docs/MATCHING_COOKBOOK.md b/docs/MATCHING_COOKBOOK.md
index 5c74f4f..54e0400 100644
--- a/docs/MATCHING_COOKBOOK.md
+++ b/docs/MATCHING_COOKBOOK.md
@@ -970,6 +970,30 @@ ADJUSTMENT and every sp-relative offset ⇒ suspect a local aggregate's row stri
 control flow.** The element type is the other half of the lever — `short` locals let cc1 drop the sign
 extension, `int` locals keep it.
 
+**PHASE 11 INSTANCE 2 — AN UNREFERENCED ARRAY LOCAL IS SIZE-LOAD-BEARING AND CONTENT-FREE.** `0x800308C4`
+(264 B, a new corpus maximum) came out **8 words from a match, and every one of the eight was the frame** —
+the `addiu sp,sp,-96` / `sw ra,88(sp)` / `sw s1,84(sp)` / `sw s0,80(sp)` prologue and its mirror epilogue,
+with **56 of 64 words already byte-identical** including every call site, delay slot and register. The
+missing 8 bytes are an **unreferenced array local**, and the mechanism is measured:
+
+| trailing declaration | vars | frame | result |
+|---|---|---|---|
+| (none) | 56 | 88 | DIFF, 8 words |
+| `int pad0, pad1;` (2 unreferenced **scalars**) | 56 | 88 | DIFF, 8 words — **cc1 gives unreferenced scalars no home** |
+| `short t[12]` (one 24-byte array) | 56 | 88 | DIFF, 8 words |
+| `int pad[2]` (unreferenced 8-byte **array**) | 64 | **96** | **MATCH** |
+| `short pad[4]` (unreferenced 8-byte **array**) | 64 | **96** | **MATCH** |
+
+**cc1 allocates stack space for an unreferenced ARRAY local but not for an unreferenced SCALAR local**, and
+the original declares one more array local than its emitted code touches. The 8 bytes are
+**size-load-bearing and content-free** — any 8-byte array reproduces them. That is a limit of the
+reconstruction, not a recovered fact, and it must be recorded as such in the file header.
+
+**AMENDED RULE: when the residual IS the frame, vary the local aggregate's declaration in THREE directions
+— element type, row stride, AND total size.** Instance 1 (`0x8009F6A0`) needed the **row stride**
+(`int t[3][4]` not `int t[9]`); instance 2 (`0x800308C4`) needed the **total size** (an unreferenced 8-byte
+array). Two instances, two different directions, same diagnostic.
+
 ### 60. A new trapped class: compiler-generated division checks (`div` + `break`)
 
 `break` **never** appears without `div` and `div` **never** appears without `break` — 75 worklist rows,