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<title>ThinkPad R400</title>
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<h1 id="pagetop">ThinkPad R400</h1>
<p</p>
<p>
It is believed that all R400 laptops are compatible.
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<p>
There are two possible flash chip sizes for the R400: 4MiB (32Mbit) or 8MiB (64Mbit).
This can be identified by the type of flash chip below the palmrest: 4MiB is SOIC-8, 8MiB
is SOIC-16.
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<p>
<b>The R400 laptops come with the ME (and sometimes AMT in addition) before flashing libreboot. Libreboot disables and removes it
by using a modified descriptor: see <a href="gm45_remove_me.html">gm45_remove_me.html</a></b> (contains notes, plus
instructions)
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<p>
Flashing instructions can be found at <a href="../install/index.html#flashrom">../install/index.html#flashrom</a>
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<p>
<a href="index.html">Back to previous index</a>.
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<h2 id="compatibility_noblobs">Compatibility (without blobs)</h2>
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Usual limitations apply for native graphics initialization
(no VBT and/or INT10H and only GRUB works so no BIOS, so no DOS/Windows support
- who cares? There is no system but GNU, and Linux is one of it's kernels).
</p>
<p>
When connecting the AC adapter while system is powered off, system will then power on.
This probably happens in coreboot aswell (with or without blobs).
It's a minor annoyance, but it should be fixed (if it's not already fixed by now).
</p>
<p>
This method of disabling the ME leaves the flash descriptor and gbe in place (non-functional data, fully documented)
and disables the ME using soft straps. This means that the gigabit ethernet will still work (putting the machine in
non-descriptor mode would wipe it out).
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<h3 id="hwvirt">Hardware virtualization (vt-x)</h3>
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The R400, when run without CPU microcode updates in coreboot, currently kernel panics
if running QEMU with vt-x enabled on 2 cores for the guest. With a single core enabled
for the guest, the guest panics (but the host is fine). Working around this in QEMU
might be possible; if not, software virtualization should work fine (it's just slower).
</p>
<p>
The following errata datasheet from Intel might help with investigation:
<a href="http://download.intel.com/design/mobile/specupdt/320121.pdf">http://download.intel.com/design/mobile/specupdt/320121.pdf</a>
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<p>
Copyright © 2014, 2015 Francis Rowe <info@gluglug.org.uk><br/>
This document is released under the Creative Commons Attribution-ShareAlike 4.0 International Public License and all future versions.
A copy of the license can be found at <a href="../license.txt">../license.txt</a>.
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This document is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See <a href="../license.txt">../license.txt</a> for more information.
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