make installkernel doesn't find built MYKERNEL

[Erratus]

After csup 6.4-RELEASE-p1 I have done:
# cd/usr/src
# make buildworld

Then created a new configuration file /root/kernels/MYKERNEL

# make buildkernel KERNCONF=MYKERNEL
completed succesfully. Created files are found in /usr/obj/usr/src/sys/MYKERNEL

Then
# make installkernel KERNCONF=MYKERNEL

fails like this:
cd /usr/obj/usr/src/sys/MYKERNEL
.../...
make KERNEL=kernel install
You must build a kernel first.
*** Error Code 1

Stop in /usr/obj/usr/src/sys/MYKERNEL.
*** Error Code 1

Stop in /usr/src.
*** Error Code 1

Stop in /usr/src.

Have RTFM and googled but no cue what's wrong. Please give a friendly hint.

[crsd]

Are you sure kernel build was completed successfully? Can you paste several last lines from `make -DNO_KERNELCLEAN buildkernel KERNCONF=MYKERNEL`?

[Erratus]

`make -DNO_KERNELCLEAN buildkernel KERNCONF=MYKERNEL`?

Have done. Thanks for the very fast answer.
Build takes several hours. Can you please explain in meantime what make -DNO_KERNELCLEAN means?

[crsd]

from /usr/src/Makefile.inc1:
-DNO_KERNELCLEAN do not run ${MAKE} clean in ${MAKE} buildkernel

so it shouldn't really rebuild anything, just re-link the kernel if compile was successful previously.

[graudeejs]

you can add KERNCONF=mykernname to /etc/make.conf
next time you build kernel you won't need to specify KERNCONF manually

[Erratus]

make -DNO_KERNELCLEAN buildkernel KERNCONF=MYKERNEL
did run for an hour or so, but far less as first run.

A reason for the problem could be that /usr had no free space left.

Make installkernel and make installworld finished with no errors after freeing some space on /usr.

Many thanks for quick responses.