Index: sys/dev/hyperv/netvsc/if_hnvar.h
===================================================================
--- sys/dev/hyperv/netvsc/if_hnvar.h
+++ sys/dev/hyperv/netvsc/if_hnvar.h
@@ -36,8 +36,7 @@
 #define HN_RXBUF_SIZE			(16 * 1024 * 1024)
 #define HN_RXBUF_SIZE_COMPAT		(15 * 1024 * 1024)
 
-/* Claimed to be 12232B */
-#define HN_MTU_MAX			(9 * 1024)
+#define HN_MTU_MAX			(65535 - ETHER_ADDR_LEN)
 
 #define HN_TXBR_SIZE			(128 * PAGE_SIZE)
 #define HN_RXBR_SIZE			(128 * PAGE_SIZE)