DF-3639: this trigger requires bnx(4) hardware (BCM5717/5718/5719/5720/577xx).
On such a system: configure the NIC, force the device to write
bge_len > 2050 (or < 18) into an RX return-ring BD, then capture
the handed-up frame (tcpdump -i bnx0 -w out.pcap) and verify the
captured frame length exceeds MCLBYTES - ETHER_ALIGN (2046).
===EVIDENCE===
DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026     root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC  x86_64
		61 pci/if_bnx
NO_BROADCOM_DEVICE
vtnet0 lo0
sysctl: unknown oid 'hw.bnx'
MD5 (/usr/src/sys/dev/netif/bnx/if_bnx.c) = 49a18c4b7642b9b2ebd1d02ad11542e4