diff --git a/docs/BOM.md b/docs/BOM.md
index 4e2710e..4512b80 100644
--- a/docs/BOM.md
+++ b/docs/BOM.md
@@ -39,6 +39,9 @@ All ports are taken.
 - The mainline kernel driver `peak_usb` is not compiled into the NVIDIA Tegra kernel (JetPack r36.4), so PEAK's proprietary driver is required.
 - Must be built with `NET=NETDEV_SUPPORT` for standard SocketCAN tools (`candump`, `ip link`, etc.).
 - The module lives at `/lib/modules/$(uname -r)/misc/pcan.ko` and is loaded via `modprobe pcan`.
+- **Staying on USB (2026-10-12)** rather than moving to the onboard controller (optional header J17 + a 3.3 V transceiver): the USB cable
+  makes the car connection easy to detach and reattach, which a header-mounted transceiver would need a bulky connector (e.g. 4-pin DTM)
+  to match.
 - Jetson Orin Nano has a built-in CAN controller (exposed by GPIO pins). Kernel `canN` order is not stable, so both are pinned by udev: onboard → `can_onboard`, PCAN-USB → `can_pcan` ([device naming](impl/reports/DEVICE-NAMING.md)).  
 
 ## Waveshare SIM7600G-H-M.2