freebsd-update fetch trying to update custom kernel

[Denis]

Hi,

I have FreeBSD 9.0 (p4) with custom kernel.

 "uname -i" says it:
HOMEWIFI90

However, when I run "freebsd-update fetch" command it would like to
update my kernel as well:

freebsd-update fetch
Looking up update.FreeBSD.org mirrors... 3 mirrors found.
Fetching metadata signature for 9.0-RELEASE from update5.FreeBSD.org... done.
Fetching metadata index... done.
Inspecting system... done.
Preparing to download files... done.

The following files are affected by updates, but no changes have
been downloaded because the files have been modified locally:
/var/db/mergemaster.mtree

The following files will be updated as part of updating to 9.0-RELEASE-p4:
/boot/kernel/kernel
/boot/kernel/kernel.symbols

What is wrong with it? If I'm not mistaken, this problem first
appeared in 9.0-RELEASE-p2, before this everything worked fine.
How can I fix this error?

Best regards,
Pi