diff --git a/system/drivers/usb-xhci-bus/usb-xhci-bus.zig b/system/drivers/usb-xhci-bus/usb-xhci-bus.zig
index 339e646..5a24e70 100644
--- a/system/drivers/usb-xhci-bus/usb-xhci-bus.zig
+++ b/system/drivers/usb-xhci-bus/usb-xhci-bus.zig
@@ -196,6 +196,18 @@ fn scanPorts(manager: runtime.ipc.Handle) void {
     };
     std.log.info("{d} root-hub ports", .{engine.max_ports});
 
+    // Diagnostic: dump every root port's raw PORTSC (CCS = connect, PED =
+    // enabled, PLS = link state, speed) so a USB2 companion hub that isn't
+    // enumerating is visible — is it connected on a port we misread, or absent?
+    {
+        var p: u32 = 1;
+        while (p <= engine.max_ports) : (p += 1) {
+            const portsc = engine.portStatus(p);
+            if (portsc & 1 != 0 or (portsc >> 5) & 0xF != 5) // connected, or not in the disabled/disconnected link state
+                std.log.info("PORTSC[{d}] = 0x{x:0>8} ccs={d} ped={d} pls={d} speed={d}", .{ p, portsc, portsc & 1, (portsc >> 1) & 1, (portsc >> 5) & 0xF, (portsc >> 10) & 0xF });
+        }
+    }
+
     var port: u32 = 1;
     var connected: u32 = 0;
     while (port <= engine.max_ports) : (port += 1) {
@@ -493,7 +505,9 @@ fn onNotification(badge: u64) void {
         engine.pump();
         while (engine.takePortChange()) |port| {
             const manager = manager_handle orelse break;
-            if (engine.portConnected(port)) {
+            const connected = engine.portConnected(port);
+            std.log.info("root port {d} change: {s} (PORTSC 0x{x:0>8})", .{ port, if (connected) "connected" else "empty", engine.portStatus(port) });
+            if (connected) {
                 if (engine.deviceOnPort(port) == null) bringUpPort(manager, engine, port);
             } else {
                 tearDownPort(manager, engine, port);