diff --git a/share/man/man4/usb_quirk.4 b/share/man/man4/usb_quirk.4
--- a/share/man/man4/usb_quirk.4
+++ b/share/man/man4/usb_quirk.4
@@ -100,6 +100,8 @@
 select configuration index 0 by default
 .It UQ_ASSUME_CM_OVER_DATA
 assume cm over data feature
+.It UQ_IGNORE_CDC_CM
+ignore cm descriptor
 .It UQ_WMT_IGNORE
 device should be ignored by wmt driver
 .El
diff --git a/sys/dev/usb/quirk/usb_quirk.h b/sys/dev/usb/quirk/usb_quirk.h
--- a/sys/dev/usb/quirk/usb_quirk.h
+++ b/sys/dev/usb/quirk/usb_quirk.h
@@ -66,6 +66,7 @@
 	UQ_CFG_INDEX_4,		/* select configuration index 4 by default */
 	UQ_CFG_INDEX_0,		/* select configuration index 0 by default */
 	UQ_ASSUME_CM_OVER_DATA,	/* assume cm over data feature */
+	UQ_IGNORE_CDC_CM,	/* ignore cm descriptor */
 
 	/*
 	 * USB Mass Storage Quirks. See "storage/umass.c" for a
diff --git a/sys/dev/usb/quirk/usb_quirk.c b/sys/dev/usb/quirk/usb_quirk.c
--- a/sys/dev/usb/quirk/usb_quirk.c
+++ b/sys/dev/usb/quirk/usb_quirk.c
@@ -662,6 +662,7 @@
 	[UQ_CFG_INDEX_4]	= "UQ_CFG_INDEX_4",
 	[UQ_CFG_INDEX_0]	= "UQ_CFG_INDEX_0",
 	[UQ_ASSUME_CM_OVER_DATA]	= "UQ_ASSUME_CM_OVER_DATA",
+	[UQ_IGNORE_CDC_CM]	= "UQ_IGNORE_CDC_CM",
 	[UQ_MSC_NO_TEST_UNIT_READY]	= "UQ_MSC_NO_TEST_UNIT_READY",
 	[UQ_MSC_NO_RS_CLEAR_UA]		= "UQ_MSC_NO_RS_CLEAR_UA",
 	[UQ_MSC_NO_START_STOP]		= "UQ_MSC_NO_START_STOP",
diff --git a/sys/dev/usb/serial/umodem.c b/sys/dev/usb/serial/umodem.c
--- a/sys/dev/usb/serial/umodem.c
+++ b/sys/dev/usb/serial/umodem.c
@@ -359,7 +359,9 @@
 
 	/* get the data interface number */
 
-	cmd = umodem_get_desc(uaa, UDESC_CS_INTERFACE, UDESCSUB_CDC_CM);
+	cmd = NULL;
+	if (!usb_test_quirk(uaa, UQ_IGNORE_CDC_CM))
+		cmd = umodem_get_desc(uaa, UDESC_CS_INTERFACE, UDESCSUB_CDC_CM);
 
 	if ((cmd == NULL) || (cmd->bLength < sizeof(*cmd))) {
 		cud = usbd_find_descriptor(uaa->device, NULL,