OpnSense startet nicht ohne angeschlossenen Monitor

Some systems may fail to start FreeBSD / OPNsense / pfSense if no monitor is connected during the startup process. To solve this problem, the tunable hw.uart.console = default can be set. Alternatively, disabling all COM ports in the BIOS or a serial console as primary console will result in a correct boot process even if the monitor is disconnected.

Affected systems

Affected systems are e.g.

• LES plus v3 with Default BIOS Settings & EFI Boot (tested with BIOS Version: CM2LA170 / Build Date: 13.06.2022)
• LES v4 with Default BIOS Settings & EFI Boot (tested with BIOS Version: YELU3L12 / Build Date: 24.10.2022)

Cause

There was a bug in FreeBSD 13 that did not handle serial EFI consoles. This bug was fixed in OPNsense 22.1.2, but in general FreeBSD 13 requires the BIOS to disable legacy UART emulation.^[1][2]

Possible solutions

To resolve this issue, perform one of the following resolution options:

• Tunable hw.uart.console ergänzen
• COM Port disablen im BIOS
• Primary Console: Serial Console

Add Tunable hw.uart.console

To fix the problem, set the Tuneable hw.uart.console and then reboot the system:

1. Under System ‣ Settings ‣ Tunable click the +' Icon (Add)
2. Add the value default to the Tuneable hw.uart.console':

   

3. Click on Apply Changes:

   

4. The setting has been applied:

   

5. Perform a restart.

With this tunable, the dmesg output shows an additional line with uart0: console (115200,n,8,1) on a subsequent reboot - a boot process without a monitor connected works with this:

root@fw-test-opnsense-22-7:~ # dmesg | grep -i uart
 uart0: <16550 or compatible> port 0x3f8-0x3ff irq 4 flags 0x10 on acpi0
 uart0: console (115200,n,8,1)
 root@fw-test-opnsense-22-7:~ # 

Disable COM Ports in BIOS

If all COM ports are disabled in the BIOS, the system will boot even without a monitor connected.^[3]

Primary Console: Serial Console

By default, the VGA Console is configured as the Primary Console.

• System ‣ Settings ‣ Administration shows in the area Console:

  

To ensure that the system starts reliably even without a monitor connected, configure the Serial Console as Primary Console (see also OPNsense serial console). Then use the VGA console only as secondary console:^[4]

• In System ‣ Settings ‣ Administration choose the following settings in the area Consoleand save them:
  • Primary Console: Serial Console
  • Secondary Console: VGA Console
• The settings look like this: