8.5 - Boot Time Configuration

Sometimes when booting your system you might notice that the kernel finds your device but maybe at the wrong IRQ. And maybe you need to use this device right away. Well, without rebuilding the kernel you can use MicroBSD's boot time kernel configuration. This will only correct your problem for one time. If you reboot, you will have to repeat this procedure. So, this is only meant as a temporary fix, and you should correct the problem by fixing and recompiling your kernel. Your kernel does however need option BOOT_CONFIG in the kernel, which GENERIC does have.

To boot into the User Kernel Config, or UKC, at boot time use the -c option.

    boot> boot wd0a:/bsd -c 
    

Or whichever kernel it is you want to boot. Doing this will bring up a UKC prompt. From here you can issue commands directly to the kernel specifying devices you want to change or disable or even enable.

Here is a list of common commands in the UKC.

• add device - Add a device through copying another.
• change devno | device - Modify one or more devices.
• disable devno | device - Disable one or more devices.
• enable devno | device - Enable one or more devices.
• find devno | device - Find one or more devices.
• help - Short summary of these commands.
• list - List ALL known devices.
• exit/quit - Continue Booting.
• show [attr [val]] - Show devices with an attribute and optional with a specified value.

Once you get your device configured, use quit or exit and continue booting. After doing so you should correct your Kernel configuration and Compile a new kernel.

8.5.1 - Getting more verbose output during boot

Getting more verbose output can be very helpful when trying to debug problems when booting. If you have a problem wherein your boot floppy won't boot and need to get more information, simply reboot. When you get to the "boot>" prompt, boot with boot -c. This will bring you into the UKC>, then do:

   UKC> verbose
   autoconf verbose enabled
   UKC> quit
   

Now you will be given extremely verbose output upon boot.

This, and other documents, can be downloaded from MicroBSD.

For questions about MicroBSD, read the documentation before contacting <MicroBSD Support>.
Copyright © 1995-2003 by The FreeBSD Documentation Project, OpenBSD FAQ Copyright © 1998-2003 OpenBSD, Modified for MicroBSD