Getting Broadcom NetXtreme II BCM57800 Gigabit Ethernet Working

Hello Zorin forum. I recently tried to install Zorin OS Pro 16.1 on a Dell R720. After a day of attempting to get the ethernet adapter working, I gave up and installed CentOS 7 instead, which includes the driver in the installer and doesn't require anything special.

I attempted to follow half a dozen different guides on how to get this driver working but I wasn't able to get any of the methods to work. Most everything I found was for either Debian or Ubunutu. I didn't find any guides for this driver with Zorin OS.

CentOS is working just fine on the system but I'd really like to get Zorin OS installed instead.

Has anyone been able to figure out how to get a driver for this ethernet adapter working in Zorin OS?

Here's the output of inxi -Faz running CentOS

System:
  Kernel: 3.10.0-862.el7.x86_64 arch: x86_64 bits: 64 compiler: gcc v: 4.8.5
    parameters: BOOT_IMAGE=/vmlinuz-3.10.0-862.el7.x86_64
    root=/dev/mapper/centos-root ro rd.lvm.lv=centos/root
    rd.lvm.lv=centos/swap rhgb quiet LANG=en_US.UTF-8
  Console: pty pts/0 Distro: CentOS Linux release 7.5.1804 (Core)
Machine:
  Type: Server System: Dell product: Dell DR4100 v: N/A serial: <filter>
    Chassis: type: 23 serial: <filter>
  Mobo: Dell model: 0X3D66 v: A02 serial: <filter> BIOS: Dell v: 2.5.2
    date: 01/28/2015
CPU:
  Info: model: Intel Xeon E5-2620 0 socket: LGA2011 bits: 64 type: MT MCP SMP
    arch: Sandy Bridge family: 6 model-id: 0x2D (45) stepping: 7
    microcode: 0x710
  Topology: cpus: 2x cores: 6 tpc: 2 threads: 12 smt: N/A cache:
    L1: 2x 384 KiB (768 KiB) desc: d-6x32 KiB; i-6x32 KiB
    L2: 2x 1.5 MiB (3 MiB) desc: 6x256 KiB L3: 2x 15 MiB (30 MiB)
    desc: 1x15 MiB
  Speed (MHz): avg: 2300 min/max: 1200/2500 base/boost: 2000/3600 scaling:
    driver: intel_pstate governor: powersave volts: 1.2 V ext-clock: 7200 MHz
    cores: 1: 2300 2: 2300 3: 2300 4: 2300 5: 2300 6: 2300 7: 2300 8: 2300
    9: 2300 10: 2300 11: 2300 12: 2300 13: 2300 14: 2300 15: 2300 16: 2300
    17: 2300 18: 2300 19: 2300 20: 2300 21: 2300 22: 2300 23: 2300 24: 2300
    bogomips: 96043
  Flags: avx ht lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx
  Vulnerabilities:
  Type: meltdown mitigation: PTI
  Type: spectre_v1 mitigation: Load fences
  Type: spectre_v2 status: Vulnerable: Retpoline without IBPB
Graphics:
  Device-1: Matrox Systems G200eR2 vendor: Dell driver: mgag200 v: kernel
    ports: active: VGA-1 empty: none bus-ID: 0a:00.0 chip-ID: 102b:0534
    class-ID: 0300
  Display: server: X.org v: 1.20.4 driver: gpu: mgag200 note:  X driver n/a
    tty: 80x49
  Monitor-1: VGA-1 model: ViewSonic VA1912w-3 serial: <filter> built: 2006
    res: 1440x900 dpi: 89 gamma: 1.2 size: 410x260mm (16.14x10.24")
    diag: 485mm (19.1") ratio: 16:10 modes: max: 1440x900 min: 640x480
  Message: Unable to show GL data. Required tool glxinfo missing.
Audio:
  Message: No device data found.
Network:
  Device-1: Broadcom NetXtreme II BCM57800 1/10 Gigabit Ethernet vendor: Dell
    driver: bnx2x v: 1.712.30-0 port: N/A bus-ID: 01:00.0 chip-ID: 14e4:168a
    class-ID: 0200
  IF: em1 state: down mac: <filter>
  Device-2: Broadcom NetXtreme II BCM57800 1/10 Gigabit Ethernet
    vendor: Dell driver: bnx2x v: 1.712.30-0 port: N/A bus-ID: 01:00.1
    chip-ID: 14e4:168a class-ID: 0200
  IF: em2 state: down mac: <filter>
  Device-3: Broadcom NetXtreme II BCM57800 1/10 Gigabit Ethernet
    vendor: Dell driver: bnx2x v: 1.712.30-0 port: N/A bus-ID: 01:00.2
    chip-ID: 14e4:168a class-ID: 0200
  IF: em3 state: down mac: <filter>
  Device-4: Broadcom NetXtreme II BCM57800 1/10 Gigabit Ethernet
    vendor: Dell driver: bnx2x v: 1.712.30-0 port: N/A bus-ID: 01:00.3
    chip-ID: 14e4:168a class-ID: 0200
  IF: em4 state: up speed: 1000 Mbps duplex: full mac: <filter>
RAID:
  Hardware-1: LSI Logic / Symbios Logic MegaRAID SAS 2208 [Thunderbolt]
    driver: megaraid_sas v: 07.702.06.00-rh2 port: fc00 bus-ID: 02:00.0
    chip-ID: 1000:005b rev: N/A class-ID: 0104
  Hardware-2: LSI Logic / Symbios Logic MegaRAID SAS 2208 [Thunderbolt]
    driver: megaraid_sas v: 07.702.06.00-rh2 port: ec00 bus-ID: 04:00.0
    chip-ID: 1000:005b rev: N/A class-ID: 0104
  Hardware-3: Marvell Device driver: N/A v: N/A port: N/A bus-ID: 42:00.0
    chip-ID: 11ab:8180 rev: N/A class-ID: 0104
Drives:
  Local Storage: total: 8.45 TiB lvm-free: 4 MiB used: 3.92 GiB (0.0%)
  SMART Message: Required tool smartctl not installed. Check --recommends
  ID-1: /dev/sda maj-min: 8:0 vendor: Dell PowerEdge RAID Card
    model: PERC H710P size: 278.88 GiB block-size: physical: 512 B
    logical: 512 B type: N/A serial: N/A rev: 3.13 scheme: MBR
  ID-2: /dev/sdb maj-min: 8:16 vendor: Dell PowerEdge RAID Card
    model: PERC H710P size: 8.18 TiB block-size: physical: 512 B logical: 512 B
    type: N/A serial: N/A rev: 3.13 scheme: GPT
Partition:
  ID-1: / raw-size: 50 GiB size: 49.98 GiB (99.95%) used: 3.79 GiB (7.6%)
    fs: xfs block-size: 512 B dev: /dev/dm-0 maj-min: 253:0 mapped: centos-root
  ID-2: /boot raw-size: 1024 MiB size: 1014 MiB (99.02%)
    used: 131.4 MiB (13.0%) fs: xfs block-size: 512 B dev: /dev/sda1
    maj-min: 8:1
Swap:
  Kernel: swappiness: 60 (default) cache-pressure: 100 (default)
  ID-1: swap-1 type: partition size: 15.69 GiB used: 0 KiB (0.0%)
    priority: -1 dev: /dev/dm-1 maj-min: 253:1 mapped: centos-swap
Sensors:
  System Temperatures: ipmi cpu: N/A mobo: N/A
  Fan Speeds (RPM): ipmi cpu: 9240 mobo: 9360 fan-2: fan-3: 9240
    fan-4: 8880 fan-5: 9360 fan-6: 9120
  Power: ipmi 12v: N/A 5v: N/A 3.3v: N/A vbat: N/A dimm-p1: N/A
    dimm-p2: N/A
  System Temperatures: lm-sensors cpu: 59.0 C mobo: N/A
  Fan Speeds (RPM): lm-sensors N/A
Info:
  Processes: 268 Uptime: 1d 12m wakeups: 0 Memory: 31.37 GiB
  used: 4.43 GiB (14.1%) Init: systemd v: 219 runlevel: 3
  target: multi-user.target tool: systemctl Compilers: gcc: 4.8.5
  Packages: N/A note: see --pkg Shell: Bash v: 4.2.46 running-in: pty pts/0
  inxi: 3.3.14

Here's the output of lspci for the ethernet cards:

01:00.0 Ethernet controller: Broadcom Limited NetXtreme II BCM57800 1/10 Gigabit Ethernet (rev 10)
01:00.1 Ethernet controller: Broadcom Limited NetXtreme II BCM57800 1/10 Gigabit Ethernet (rev 10)
01:00.2 Ethernet controller: Broadcom Limited NetXtreme II BCM57800 1/10 Gigabit Ethernet (rev 10)
01:00.3 Ethernet controller: Broadcom Limited NetXtreme II BCM57800 1/10 Gigabit Ethernet (rev 10)

Zorin OS is based on Ubuntu, so using the Ubuntu guide should work just fine. In the case of Zorin OS 16, it is based on Ubuntu 20.04.
The Broadcom driver is included in the Modules-extra package with the kernel.
So installing the kernel modules extra package should work in most cases.
Otherwise, this very In Depth Guide here should cover the rest: