diff --git a/sim_ether.h b/sim_ether.h
index 96e56f81..4a0dbcb0 100644
--- a/sim_ether.h
+++ b/sim_ether.h
@@ -160,7 +160,7 @@ extern "C" {
 #define ETH_MIN_PACKET        60                        /* minimum ethernet packet size */
 #define ETH_MAX_PACKET      1514                        /* maximum ethernet packet size */
 #define ETH_MAX_JUMBO_FRAME 65536                       /* maximum ethernet jumbo frame size (or Offload Segment Size) */
-#define ETH_MAX_DEVICE        20                        /* maximum ethernet devices */
+#define ETH_MAX_DEVICE        40                        /* maximum ethernet devices */
 #define ETH_CRC_SIZE           4                        /* ethernet CRC size */
 #define ETH_FRAME_SIZE (ETH_MAX_PACKET+ETH_CRC_SIZE)    /* ethernet maximum frame size */
 #define ETH_MIN_JUMBO_FRAME ETH_MAX_PACKET              /* Threshold size for Jumbo Frame Processing */