S12v7: drop add-sp (marched)

tools/sbl_uni.py

@@ -457,18 +457,18 @@ def main():
     # to the dispatcher via stale lr (TZ bringup deferred).
     # NOTE: overwrites 4B of real ARM trampoline (recoverable from ELF).
     mu.mem_write(0x00221EF8, bytes([0x00, 0x20, 0x70, 0x47]))
-    # S12-stub (b27, 108B @0x08006964, ARM): blx-to-padding becomes
+    # S12-stub (b27, 100B @0x08006964, ARM): blx-to-padding becomes
     # smart dispatcher: ldr ip,[sp,#4] (=pushed lr); ip==STUBV/even/
     # non-code => ip=poll resumption 0x8007779; else keep pushed-lr
-    # AND add sp,#8 (pop the helper frame B66 skips! un-leak!);
-    # restore r7; ACK peripheral bit1 ([literal]); bx lr.
+    # (NO add-sp: marches on mid-entries! un-leak dropped, helper-leak
+    # down is harmless); restore r7; ACK peripheral bit1; bx lr.
     # PBL would place the real ARM helper here.
     mu.mem_write(0x08006964, bytes.fromhex(
-        "04c09de58d3b06e3003840e303005ce10b00000a0100"
-        "1ce30900000a2c3ca0e1080053e30100001a08d08de2"
-        "060000ea2c3ea0e1080053e30100001a08d08de20100"
-        "00ea79c707e300c840e300700ae3737040e30c309fe5"
-        "002093e5022082e3002083e51eff2fe100a17300"))
+        "04c09de58d3b06e3003840e303005ce10900000a0100"
+        "1ce30700000a2c3ca0e1080053e30000001a050000ea"
+        "2c3ea0e1080053e30000001a010000ea79c707e300c8"
+        "40e300700ae3737040e30c309fe5002093e5022082e3"
+        "002083e51eff2fe100a17300"))
     # S16-stublet (b27, 64B @0x08006CC0): smart return for B66 bx ip.
     # ip==STUBV (fill/maze, never a legit return) => default;
     # ip odd + top 8 (code) => add sp,#8 (pop the helper frame B66