FYI: Kernel crash and no old kernel available

[eyebone]

hej folks,

after several years using freebsd i had my first(lucky me ehh??) kernel which wasn't booting my system(kernel traps in a loop). no problem i thought, as i knew kernel.old should be created on every new kernelinstall via:

cd /usr/src; make installkernel KERNCONF=mykernel

but, kernel.old is not created on the destination folder if you use

cd /usr/src; make installkernel KERNCONF=mykernel DESTDIR=/mnt/bootdevice

in this case the kernel at bootdevice is just overwritten. just to let you know, to create a backup of your working kernel before overwritting it

(maybe this is common knowledge or i misunderstood something, please enlighten me in this case :stud)

best regards,

 

[phoenix]

This is why you should always install to a new directory (use KODIR=/boot/kernel.new and not DESTDIR), and use nextboot() to tell the loader to use the new kernel for 1 reboot only.

If that kernel fails for any reason, just reboot, and the loader will use /boot/kernel as per normal.

If the new kernel works, then just # mv /boot/kernel /boot/kernel.old; mv /boot/kernel.new /boot/kernel.

 

[eyebone]

This is why you should always install to a new directory (use KODIR=/boot/kernel.new and not DESTDIR), and use nextboot() to tell the loader to use the new kernel for 1 reboot only.

nice, i never recognized KODIR and nextboot, thx phoenix