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authorFrancis Rowe <info@gluglug.org.uk>2014-12-22 06:42:35 (EST)
committer Francis Rowe <info@gluglug.org.uk>2014-12-22 06:42:35 (EST)
commit82e8d082e74de2e17896a9fef9a2949d0c131db8 (patch)
tree04aef523a23e41bbdbb474db985bf718beed4e03
parent479940cf1b7b166dd6884a996f7ade7e2b216de9 (diff)
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docs/hcl/x200_remove_me.html: Add info about faulty Gbe regions
-rw-r--r--docs/hcl/x200_remove_me.html16
1 files changed, 11 insertions, 5 deletions
diff --git a/docs/hcl/x200_remove_me.html b/docs/hcl/x200_remove_me.html
index b1a88e2..0cef79b 100644
--- a/docs/hcl/x200_remove_me.html
+++ b/docs/hcl/x200_remove_me.html
@@ -264,18 +264,24 @@ DD CC 18 00 11 20 17 00 DD DD 18 00 12 20 17 00
<h3 id="gbe_region_changemacaddress">GBE region: change MAC address</h3>
<p>
- According to the datasheet, it's supposed to add up to 0xBABA but can actually be 0x3ABA.
- Either the checksum doesn't matter or the most significant bit of the checksum isn't checked.
+ According to the datasheet, it's supposed to add up to 0xBABA but can actually be others on the X200.
<a href="https://communities.intel.com/community/wired/blog/2010/10/14/how-to-basic-eeprom-checksums">https://communities.intel.com/community/wired/blog/2010/10/14/how-to-basic-eeprom-checksums</a>
</p>
<p>
<i>&quot;One of those engineers loves classic rock music, so he selected 0xBABA&quot;</i>
</p>
+ <p>In honour of the song <i>Baba O'Reilly</i> by <i>The Who</i> apparently. We're not making this stuff up...</p>
+
<p>
- 0xBABA and 0x3ABA only differ by the most significant bit. The checksum of the GBe region from an X200S
- was found to be 0x34BA; again, it should be 0xBABA. 34BA is actually BABA in L33T speak (look it up).
+ 0x3ABA, 0x34BA, 0x40BA and more have been observed in the main Gbe regions on the X200 factory.rom dumps.
+ The checksums of the backup regions match BABA, however.
+ </p>
+
+ <p>
+ By default, the X200 (as shipped by Lenovo) actually has an invalid main gbe checksum. The backup gbe region is correct,
+ and is what these machines default to. Basically, you should do what you need on the *backup* gbe region, and
+ then correct the main one by copying from the backup.
</p>
- <p>In honour of the song <i>Baba O'Reilly</i> by <i>The Who</i> apparently. We're not making this stuff up...</p>
<p>
Look at resources/utilities/ich9deblob/ich9deblob.c.