diff --git a/docs/SETUP.md b/docs/SETUP.md
index bf16bf2..de27469 100644
--- a/docs/SETUP.md
+++ b/docs/SETUP.md
@@ -88,7 +88,15 @@ patch, and diffing the result against the working tree (byte-identical). It adds
   after a branch/jump so GNU `as` can fill the slot.
 - `--nop-on-reg-read` (region token `maspsx=regread`) — extend the load-delay predicate (cookbook
   finding 27) so a following `jr`/`jalr` that *uses* the loaded register also gets the delay `nop`.
-- **A default-on fix (no region token): maspsx now honours cc1's explicit `#nop` marker.** cc1 emits the
+- **`nopmarker` (region token `maspsx=nopmarker`) — OPT-IN as of Phase 11.** cc1 emits an explicit
+  `#nop` marker when it thinks a load-delay nop is needed. For a bare-symbol store consumer
+  (`sw $2,D_801221C4`) the store's own `lui $at` expansion fills the delay slot, so the marker is
+  **spurious** and honouring it costs an instruction (worker C's `0x800AFDBC`: the original is
+  `lhu` / `lui at` / `sh` with NO nop). But `0x80107C5C` genuinely wants the nop (112 vs 108).
+  Phase 10 made the honouring unconditional and that was **too broad**; it is now per-region and
+  default OFF. Verified: `make check` green at 510 regions with it off, and `0x80107C5C` matches
+  112 B with the token and comes out 108 B LENGTH-MISMATCH without it.
+- **A default-on fix (superseded by the opt-in above): maspsx now honours cc1's explicit `#nop` marker.** cc1 emits the
   marker when it wants a load-delay nop; maspsx used to re-derive the need and could overrule cc1 for a
   **bare-symbol store** consumer (`sw $2,D_801221C4`), because `uses_at` is True for a macro store while
   `nop_at_expansion` is False for ASPSX >= 2.30, so neither test fired and the nop was dropped
diff --git a/tools/patches/maspsx-phase10-r1r2.patch b/tools/patches/maspsx-phase10-r1r2.patch
index 4204a89..cbbcc08 100644
--- a/tools/patches/maspsx-phase10-r1r2.patch
+++ b/tools/patches/maspsx-phase10-r1r2.patch
@@ -39,16 +39,15 @@
  def line_loads_from_reg(line: str, r_source: str, loads_to_reg=False) -> bool:
      """
      NOTE: Returns True even if line might use $at expansion
-@@ -448,6 +480,8 @@
-         gp_allow_la=False,
-         use_comm_section=False,
+@@ -450,6 +482,7 @@
          use_comm_for_lcomm=False,
-+        no_jump_slot_nop=False,
-+        nop_on_reg_read=False,
+         no_jump_slot_nop=False,
+         nop_on_reg_read=False,
++        honour_nop_marker=False,
      ):
          self.lines = [x.strip() for x in lines]
  
-@@ -460,6 +494,15 @@
+@@ -462,6 +495,18 @@
          self.nop_mflo_mfhi = nop_mflo_mfhi
          self.nop_lw_lw = nop_lw_lw
  
@@ -60,11 +59,14 @@
 +        #     the loaded register as needing the delay nop (worker C's R2).
 +        self.no_jump_slot_nop = no_jump_slot_nop
 +        self.nop_on_reg_read = nop_on_reg_read
++        # Opt-in (Phase 11 correction): honour cc1's explicit `#nop` marker even when
++        # the following instruction's own macro expansion would fill the delay slot.
++        self.honour_nop_marker = honour_nop_marker
 +
          self.sltu_at = sltu_at
          self.addiu_at = addiu_at
          self.div_uses_tge = div_uses_tge
-@@ -696,9 +739,30 @@
+@@ -698,9 +743,34 @@
      ) -> List[str]:
          res: List[str] = []
  
@@ -79,24 +81,28 @@
 +        if reuse:
              nop_required = False
  
-+            # Phase 10 (developer-authorised): cc1 emits an explicit `#nop` marker
-+            # when it wants a load-delay nop. maspsx used to re-derive the need and
-+            # could overrule cc1: for a BARE-SYMBOL store consumer (`sw $2,D_801221C4`)
-+            # `uses_at` is True (the store expands via $at) while `nop_at_expansion`
-+            # is False for ASPSX >= 2.30, so neither test below fired and the nop was
-+            # dropped -- losing an instruction cc1 had asked for (0x80107C5C,
-+            # 0x8003A9C8). Honour the explicit marker instead of overruling it.
-+            # Only the marker changes behaviour; every other path is untouched.
-+            if self.get_next_instruction(
++            # Phase 10/11: cc1 emits an explicit `#nop` marker when it thinks a
++            # load-delay nop is needed. For a BARE-SYMBOL store consumer
++            # (`sw $2,D_801221C4`) `uses_at` is True (the store expands via $at) while
++            # `nop_at_expansion` is False for ASPSX >= 2.30, so neither test below
++            # fires and the marker is ignored -- which is the correct default, because
++            # the store's own `lui $at` expansion fills the delay slot (worker C's
++            # 0x800AFDBC: the original is `lhu` / `lui at` / `sh` with NO nop, and
++            # honouring the marker costs 2 instructions there).
++            #
++            # Phase 10 made this unconditional and it was TOO BROAD: 0x80107C5C DOES
++            # want the nop (108 vs 112). So it is opt-in per region now
++            # (`maspsx=nopmarker`). Default off; no registered region depends on
++            # either behaviour (the gate is green at 510 regions both ways).
++            if self.honour_nop_marker and self.get_next_instruction(
 +                skip=0, ignore_nop=False, ignore_set=True, ignore_label=True
 +            ) == "#nop":
 +                reason = "cc1 emitted an explicit '#nop' marker"
 +                nop_required = True
-+
+ 
              if not uses_at(next_instruction):
                  reason = f"'{next_instruction}' does not use $at"
-                 nop_required = True
-@@ -1102,7 +1166,7 @@
+@@ -1105,7 +1175,7 @@
  
          elif op in branch_mnemonics or op in jump_mnemonics:
              res.append(line)
@@ -107,23 +113,25 @@
          elif op == "move":
 --- a/maspsx.py
 +++ b/maspsx.py
-@@ -62,6 +62,10 @@
+@@ -62,8 +62,11 @@
      parser.add_argument("--passthrough", action="store_true")
      parser.add_argument("--use-comm-section", action="store_true")
      parser.add_argument("--use-comm-for-lcomm", action="store_true")
 +    # Phase 10 local additions (developer-authorised, opt-in; see
 +    # tools/patches/maspsx-phase10-r1r2.patch and docs/SETUP.md).
-+    parser.add_argument("--no-jump-slot-nop", action="store_true")
-+    parser.add_argument("--nop-on-reg-read", action="store_true")
+     parser.add_argument("--no-jump-slot-nop", action="store_true")
+     parser.add_argument("--nop-on-reg-read", action="store_true")
++    parser.add_argument("--honour-nop-marker", action="store_true")
      # decomp.me debugging
      parser.add_argument("--print-output", action="store_true")
      parser.add_argument("--print-input", action="store_true")
-@@ -152,6 +156,8 @@
+@@ -154,6 +157,9 @@
              gp_allow_la=version_config.gp_allow_la,
              use_comm_section=args.use_comm_section,
              use_comm_for_lcomm=args.use_comm_for_lcomm,
 +            no_jump_slot_nop=args.no_jump_slot_nop,
 +            nop_on_reg_read=args.nop_on_reg_read,
++            honour_nop_marker=args.honour_nop_marker,
          )
  
      try:
diff --git a/tools/sf3_match b/tools/sf3_match
index 4ef59b2..509426e 100755
--- a/tools/sf3_match
+++ b/tools/sf3_match
@@ -216,7 +216,8 @@ _REGION_OPTION_KEYS = ("cc1", "as", "gp", "maspsx")
 #     `move`->`addu` rewrite and NO maspsx stage, letting `as` fill exactly the slots cc1
 #     left empty while leaving cc1's own `.set noreorder` windows alone.
 _MASPSX_MODES = {"off": "--off", "noreordernop": "--no-jump-slot-nop",
-                  "regread": "--nop-on-reg-read", "moves": "moves"}
+                  "regread": "--nop-on-reg-read", "moves": "moves",
+                  "nopmarker": "--honour-nop-marker"}
 
 
 def parse_region_options(text: str, line_number: int) -> tuple[tuple[str, ...], tuple[str, ...], tuple[str, ...], bool, tuple[str, ...], bool]:
@@ -852,6 +853,10 @@ def add_toolchain_arguments(parser: argparse.ArgumentParser) -> None:
     parser.add_argument("--no-jump-slot-nop", action="store_true",
                         help="maspsx mode: suppress the unconditional reorder nop after a "
                              "branch/jump so GNU as can fill the slot (region: maspsx=noreordernop)")
+    parser.add_argument("--honour-nop-marker", action="store_true",
+                        help="maspsx mode: honour cc1's explicit `#nop` marker even when the "
+                             "following macro expansion would fill the delay slot "
+                             "(region token: maspsx=nopmarker)")
     parser.add_argument("--maspsx-moves", action="store_true",
                         help="run the `move`->`addu` rewrite and NO maspsx stage, so GNU as "
                              "reorder mode fills the slots (region token: maspsx=moves)")
@@ -963,7 +968,8 @@ def resolve_toolchain(args: argparse.Namespace) -> Toolchain:
         maspsx_flags=tuple(
             flag for flag, enabled in (
                 ("--no-jump-slot-nop", getattr(args, "no_jump_slot_nop", False)),
-                ("--nop-on-reg-read", getattr(args, "nop_on_reg_read", False))) if enabled),
+                ("--nop-on-reg-read", getattr(args, "nop_on_reg_read", False)),
+                ("--honour-nop-marker", getattr(args, "honour_nop_marker", False))) if enabled),
         aspsx_version=args.aspsx_version,
     )