Если нам нужно проапгрейдить ядро до свеженького, добавляем репу wheezy-backports
echo \"deb https://ftp.debian.org/debian/ wheezy-backports main non-free contrib\" >> /etc/apt/sources.list
aptitude update
aptitude search linux-image
aptitude install linux-image-3.16.0-0.bpo.4-amd64
Далее может случиться неприятный диалог, нужно отвечать как в примере ниже.
The following NEW packages will be installed:
linux-image-3.16.0-0.bpo.4-amd64{b}
The following packages are RECOMMENDED but will NOT be installed:
irqbalance
0 packages upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 33.9 MB of archives. After unpacking 165 MB will be used.
The following packages have unmet dependencies:
linux-image-3.16.0-0.bpo.4-amd64 : Depends: initramfs-tools (>= 0.110~) but 0.109.1 is installed.
Breaks: initramfs-tools (< 0.110~) but 0.109.1 is installed.
The following actions will resolve these dependencies:
Keep the following packages at their current version:
1) linux-image-3.16.0-0.bpo.4-amd64 [Not Installed]
Accept this solution? [Y/n/q/?] n
The following actions will resolve these dependencies:
Upgrade the following packages:
1) initramfs-tools [0.109.1 (now, oldstable) -> 0.115~bpo70+1 (wheezy-backports)]
Accept this solution? [Y/n/q/?]
The following NEW packages will be installed:
linux-image-3.16.0-0.bpo.4-amd64
The following packages will be upgraded:
initramfs-tools
The following packages are RECOMMENDED but will NOT be installed:
irqbalance
1 packages upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 33.9 MB of archives. After unpacking 165 MB will be used.
Do you want to continue? [Y/n/?]
Любуемся аптаймом, открыаем КВМ и перезагружаемся в новое ядро.