2.9. Troubleshooting
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## 2.9. Troubleshooting

This section covers basic installation troubleshooting, such as common problems people have reported.

Check the Hardware Notes (https://www.freebsd.org/releases/index.html) document for the version of FreeBSD to make sure the hardware is supported. If the hardware is supported and lock-ups or other problems occur, build a custom kernel using the instructions in Chapter 8, Configuring the FreeBSD Kernel to add support for devices which are not present in the `GENERIC` kernel. The default kernel assumes that most hardware devices are in their factory default configuration in terms of IRQs, I/O addresses, and DMA channels. If the hardware has been reconfigured, a custom kernel configuration file can tell FreeBSD where to find things.

### Note:

Some installation problems can be avoided or alleviated by updating the firmware on various hardware components, most notably the motherboard. Motherboard firmware is usually referred to as the BIOS. Most motherboard and computer manufacturers have a website for upgrades and upgrade information.

Manufacturers generally advise against upgrading the motherboard BIOS unless there is a good reason for doing so, like a critical update. The upgrade process can go wrong, leaving the BIOS incomplete and the computer inoperative.

If the system hangs while probing hardware during boot, or it behaves strangely during install, ACPI may be the culprit. FreeBSD makes extensive use of the system ACPI service on the i386 and amd64 platforms to aid in system configuration if it is detected during boot. Unfortunately, some bugs still exist in both the ACPI driver and within system motherboards and BIOS firmware. ACPI can be disabled by setting the `hint.acpi.0.disabled` hint in the third stage boot loader:

    set hint.acpi.0.disabled="1"

This is reset each time the system is booted, so it is necessary to add `hint.acpi.0.disabled="1"` to the file `/boot/loader.conf`. More information about the boot loader can be found in Section 12.1, “Synopsis”.

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