/etc/apt/sources.list
deb http://ftp.us.debian.org/debian/ testing main non-free contrib
deb-src http://ftp.us.debian.org/debian/ testing main non-free contrib

deb http://security.debian.org/ testing/updates main

# apt-get -f install
Reading package lists... Done
Building dependency tree... Done
Correcting dependencies...Done
The following extra packages will be installed:
  libc6
Suggested packages:
  glibc-doc
The following packages will be upgraded:
  libc6
1 upgraded, 0 newly installed, 0 to remove and 210 not upgraded.
1 not fully installed or removed.
Need to get 0B/4405kB of archives.
After unpacking 594kB disk space will be freed.
Do you want to continue [Y/n]? y
(Reading database ... 25293 files and directories currently installed.)
Preparing to replace libc6 2.3.6.ds1-13 (using .../libc6_2.6.1-1+b1_i386.deb) ...
WARNING: POSIX threads library NPTL requires kernel version
2.6.8 or later. If you use a kernel 2.4, please upgrade it
before installing glibc.

The installation of a 2.6 kernel _could_ ask you to install a new libc
first, this is NOT a bug, and should *NOT* be reported. In that case,
please add etch sources to your /etc/apt/sources.list and run:
  apt-get install -t etch linux-image-2.6
Then reboot into this new kernel, and proceed with your upgrade
dpkg: error processing /var/cache/apt/archives/libc6_2.6.1-1+b1_i386.deb (--unpack):
 subprocess pre-installation script returned error exit status 1
Errors were encountered while processing:
 /var/cache/apt/archives/libc6_2.6.1-1+b1_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
apt-get install -t etch linux-image-2.6
Reading package lists... Done
Building dependency tree... Done
Package linux-image-2.6 is a virtual package provided by:
  linux-image-2.6.22-2-vserver-k7 2.6.22-4
  linux-image-2.6.22-2-vserver-686 2.6.22-4
  linux-image-2.6.22-2-k7 2.6.22-4
  linux-image-2.6.22-2-amd64 2.6.22-4
  linux-image-2.6.22-2-686-bigmem 2.6.22-4
  linux-image-2.6.22-2-686 2.6.22-4
  linux-image-2.6.22-2-486 2.6.22-4
You should explicitly select one to install.
E: Package linux-image-2.6 has no installation candidate


# apt-get install -t etch linux-image-2.6.22-2-686
Reading package lists... Done
Building dependency tree... Done
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies.
  linux-image-2.6.22-2-686: Depends: initramfs-tools (>= 0.55) but it is not going to be installed or
                                     yaird (>= 0.0.12-8) but it is not going to be installed or
                                     linux-initramfs-tool
  locales: Depends: glibc-2.6-1
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).

(repeats)