diff --git a/hw/usb/host-libusb.c b/hw/usb/host-libusb.c
index 7dde3d1206..354713a77d 100644
--- a/hw/usb/host-libusb.c
+++ b/hw/usb/host-libusb.c
@@ -836,7 +836,7 @@ static void usb_host_ep_update(USBHostDevice *s)
     struct libusb_ss_endpoint_companion_descriptor *endp_ss_comp;
 #endif
     uint8_t devep, type;
-    int pid, ep;
+    int pid, ep, alt;
     int rc, i, e;
 
     usb_ep_reset(udev);
@@ -848,8 +848,20 @@ static void usb_host_ep_update(USBHostDevice *s)
                                 conf->bConfigurationValue, true);
 
     for (i = 0; i < conf->bNumInterfaces; i++) {
-        assert(udev->altsetting[i] < conf->interface[i].num_altsetting);
-        intf = &conf->interface[i].altsetting[udev->altsetting[i]];
+        /*
+         * The udev->altsetting array indexes alternate settings
+         * by the interface number. Get the 0th alternate setting
+         * first so that we can grab the interface number, and
+         * then correct the alternate setting value if necessary.
+         */
+        intf = &conf->interface[i].altsetting[0];
+        alt = udev->altsetting[intf->bInterfaceNumber];
+
+        if (alt != 0) {
+            assert(alt < conf->interface[i].num_altsetting);
+            intf = &conf->interface[i].altsetting[alt];
+        }
+
         trace_usb_host_parse_interface(s->bus_num, s->addr,
                                        intf->bInterfaceNumber,
                                        intf->bAlternateSetting, true);
diff --git a/hw/usb/pcap.c b/hw/usb/pcap.c
index 4350989d3a..dbff00be25 100644
--- a/hw/usb/pcap.c
+++ b/hw/usb/pcap.c
@@ -127,6 +127,7 @@ static void do_usb_pcap_ctrl(FILE *fp, USBPacket *p, bool setup)
         .xfer_type  = usbmon_xfer_type[USB_ENDPOINT_XFER_CONTROL],
         .epnum      = in ? 0x80 : 0,
         .devnum     = dev->addr,
+        .flag_setup = setup ? 0 : '-',
         .flag_data  = '=',
         .length     = dev->setup_len,
     };
@@ -169,6 +170,7 @@ static void do_usb_pcap_data(FILE *fp, USBPacket *p, bool setup)
         .xfer_type  = usbmon_xfer_type[p->ep->type],
         .epnum      = usbmon_epnum(p),
         .devnum     = p->ep->dev->addr,
+        .flag_setup = '-',
         .flag_data  = '=',
         .length     = p->iov.size,
     };