When doing a make buildworld, it is possible to speed up the process slightly by removing all files in /usr/obj. (This is usually about 500 megabytes of space.)
# rm -rf /usr/obj/*
If a make buildworld/make buildkernel has already been performed on the machine, a "quickworld"/"quickkernel" target can be used which will build faster than the usual buildworld/buildkernel process.
# cd /usr/src
# make quickworld
# make quickkernel KERNCONF=MYKERNEL
# make installkernel KERNCONF=MYKERNEL
# make installworld
# make upgrade
If the quick targets do not work, update again and rebuild using the normal buildworld/buildkernel process.
The most recent previously installed kernel is stored as /kernel.old. If the new installed kernel has trouble booting, it is possible to use the old kernel by interrupting the boot loader during boot and typing:
> unload
> boot kernel.old
The file /var/log/messages will contain a log of any errors during boot with the non-functional kernel; check this file to diagnose problems.
Contact the Documentation Team for comments, suggestions and questions about this document.