Bring-up: D9 'USB' LED is an open solder joint, not a circuit fault

Anode-side pad at 3V3, cathode at 0V, LED dark — the full rail standing
across it means no current and no drop across R42, so Q2 and R42 are both
doing their job.  Probe pressure on the anode pad lights it at full
brightness: the terminal is sitting on the pad unwetted.  Reflow fixes it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

hardware/re-bba-rb/TODO.md

@@ -249,6 +249,20 @@ schematic changes.
       OVLO divider off 12V_RAW, R_top ≈ 1.1 M / R_bottom ≈ 100 k → trip ~15 V.
       See REVIEW.md eFuse entry. Bench workaround: feed 12 V onto 12V_EXI (C65+ /
       U3 VIN) to bypass it. This must be fixed before any V2.1 fab order.
+- [ ] **D9 "USB" LED dark — OPEN SOLDER JOINT on its anode pad (found at
+      bring-up 2026-09-30). Assembly defect on this unit, NOT a design bug.**
+      Symptom: D9 never lights, on USB-only or GC power. Measured 3V3 on the
+      anode-side pad and 0 V on the cathode with the LED dark — i.e. the full
+      rail standing across it, so no current and no drop across R42 (if D9 were
+      conducting the anode would sit at Vf ≈ 2 V). Touching the anode pad with a
+      meter probe makes it light at full brightness: the probe pressure closes
+      the joint. So Q2 (S8550 PNP) and R42 are fine and the LED itself is fine —
+      the terminal is sitting on the pad without wetting it. **Fix: flux +
+      reflow D9's anode pad** (and R42's pad on the same net, `Net-(D9-A)`,
+      while the iron is there). Cosmetic indicator only; does not affect the
+      power mux, which is working (GC/USB handover verified via D8 + rails).
+      Footprint is not suspect — D6/D8/D12 are the same reverse-mount part
+      (Everlight 24-21, C2980185) and all three light correctly.
 - [ ] **12 V inrush limiter (U13 TPS25961 eFuse) — SCHEMATIC DONE 2026-07-31**,
       full design rationale in REVIEW.md §6. J3.5 → 12V_RAW → U13 → 12V_EXI;
       D3 (TVS) stays upstream, C65 downstream. R45 100 k sets I_LIM ≈ 500 mA