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.