Disabling OpenBSD kernel device
This article describes how to disable OpenBSD kernel device which may prevent the computer from booting properly.
Change kernel device configuration at boot
Power on the computer, and wait for the boot prompt which looks like this:
Enter the boot time configuration by:
The device can be disabled using the
disable command. For
example, to disable the
amdgpu device, enter:
Continue the boot process by entering:
Apply modifications for next boot
To apply the modifications automatically for the next boot, even after a
new kernel is installed (for example, after applying a patch), and to
avoid kernel relinking failure, create the
file with the following content:
printf 'disable amdgpu\nquit\n' | config -ef /bsd sha256 /bsd >/var/db/kernel.SHA256
The first line uses
config to modify the kernel device
configuration. The second line calculates the new hash of the kernel.
On every system shutdown, the modifications are applied and the hash is calculated automatically.