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Revision 2 as of 2013-08-23 17:43:26
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Revision 3 as of 2013-08-24 07:26:36
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Comment: iucode-tool is automatically brought in as a recommended package for intel-microcode, InterWiki, formatting.
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Processors from Intel and AMD may need updates to their microcode
to operate correctly. These updates fix bugs/errata that can cause anything from incorrect processing, to code and data corruption, and system lockups.
Processors from Intel and AMD may need updates to their microcode to operate correctly. These updates fix bugs/errata that can cause anything from incorrect processing, to code and data corruption, and system lockups.
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It is very difficult to know for sure whether you need a microcode
update or not, but it is not safe at all to just ignore them. You might
not notice their effect and have precious data silently corrupted, or an
important program silently misbehave. Or you could experience one of
those unexplainable and infrequent software issues (such as kernel oops,
application segfaults) or hardware issues (including sudden reboots and
hangs).
It is very difficult to know for sure whether you need a microcode update or not, but it is not safe at all to just ignore them. You might not notice their effect and have precious data silently corrupted, or an important program silently misbehave. Or you could experience one of those unexplainable and infrequent software issues (such as kernel oops, application segfaults) or hardware issues (including sudden reboots and hangs).
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Releases of new microcode updates are more frequent on young processors,
but the release of new microcode updates for older processors do happen.
Releases of new microcode updates are more frequent on young processors, but the release of new microcode updates for older processors do happen.
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The BIOS (or EFI) updates the CPU microcode during boot, however most of
the time either the motherboard vendor won't issue frequent BIOS/EFI
updates, or the user won't install such updates. For these reasons, the
system processor is likely to be running with outdated microcode on a
vast number of systems.
The BIOS (or EFI) updates the CPU microcode during boot, however most of the time either the motherboard vendor won't issue frequent BIOS/EFI updates, or the user won't install such updates. For these reasons, the
system processor is likely to be running with outdated microcode on a vast number of systems.
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Please install the DebianPkg:amd64-microcode package (for systems with AMD AMD64 processors), or the DebianPkg:intel-microcode package (for systems with Intel processors). You will have to enable both '''contrib''' and '''non-free''' in [[SourcesList|/etc/apt/sources.list]].
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Please install the '''amd64-microcode''' package (for systems with AMD
processors), or the '''intel-microcode''' and '''iucode-tool''' packages (for
systems with Intel processors).
Debian 6.0 "Squeeze" users can find up-to-date versions of these packages in the official [[http://backports.debian.org/Instructions/|backports repository]] (in the contrib and non-free sections).
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'''iucode-tool''' is available in '''contrib''', the other two packages are
available in '''non-free''', so you will have to enable both contrib and
non-free in /etc/apt/sources.list.

Debian Squeeze users can find up-to-date versions of these packages in
the official backports repository (in the contrib and non-free
sections).

Microcode updates will be applied immediately when the microcode
packages are installed or updated: you don't have to reboot. You will
have to keep the packages installed, though: as explained above, the
microcode updates have to be reapplied at every boot.
Microcode updates will be applied immediately when the microcode packages are installed or updated: you don't have to reboot. You will have to keep the packages installed, though: as explained above, the microcode updates have to be reapplied at every boot.
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You can check which version of the microcode your processors are running
by looking for "microcode" lines on /proc/cpuinfo. This information is
only available on recent kernels (such as the Wheezy kernel).

You can check which version of the microcode your processors are running by looking for "microcode" lines on /proc/cpuinfo. This information is only available on recent kernels (such as the Debian 7 "Wheezy" kernel).
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 * [[https://en.wikipedia.org/wiki/Microcode|Microcode entry on Wikipedia]]  * [[WikiPedia:Microcode|Microcode entry on Wikipedia]]

CPU Microcode

Processor microcode is akin to processor firmware. The kernel is able to update the processor's firmware without the need to update it via a BIOS update.

Processors from Intel and AMD may need updates to their microcode to operate correctly. These updates fix bugs/errata that can cause anything from incorrect processing, to code and data corruption, and system lockups.

It is very difficult to know for sure whether you need a microcode update or not, but it is not safe at all to just ignore them. You might not notice their effect and have precious data silently corrupted, or an important program silently misbehave. Or you could experience one of those unexplainable and infrequent software issues (such as kernel oops, application segfaults) or hardware issues (including sudden reboots and hangs).

Releases of new microcode updates are more frequent on young processors, but the release of new microcode updates for older processors do happen.

The BIOS (or EFI) updates the CPU microcode during boot, however most of the time either the motherboard vendor won't issue frequent BIOS/EFI updates, or the user won't install such updates. For these reasons, the system processor is likely to be running with outdated microcode on a vast number of systems.

Updating CPU microcode within Debian (Intel or AMD)

Please install the amd64-microcode package (for systems with AMD AMD64 processors), or the intel-microcode package (for systems with Intel processors). You will have to enable both contrib and non-free in /etc/apt/sources.list.

Debian 6.0 "Squeeze" users can find up-to-date versions of these packages in the official backports repository (in the contrib and non-free sections).

Microcode updates will be applied immediately when the microcode packages are installed or updated: you don't have to reboot. You will have to keep the packages installed, though: as explained above, the microcode updates have to be reapplied at every boot.

Checking the microcode version of your CPU

You can check which version of the microcode your processors are running by looking for "microcode" lines on /proc/cpuinfo. This information is only available on recent kernels (such as the Debian 7 "Wheezy" kernel).

References