Notes
How to add firmware to Broadcom NIC
First, confirm you have the Broadcom NIC
$ lspci | grep 'Ethernet controller'
01:00.0 Ethernet controller: Broadcom Inc. and subsidiaries NetXtreme II BCM5709 Gigabit Ethernet (rev 20)
01:00.1 Ethernet controller: Broadcom Inc. and subsidiaries NetXtreme II BCM5709 Gigabit Ethernet (rev 20)
02:00.0 Ethernet controller: Broadcom Inc. and subsidiaries NetXtreme II BCM5709 Gigabit Ethernet (rev 20)
02:00.1 Ethernet controller: Broadcom Inc. and subsidiaries NetXtreme II BCM5709 Gigabit Ethernet (rev 20)
then install the firmware
sudo apt install firmware-bnx2