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46 lines
2 KiB
Markdown
46 lines
2 KiB
Markdown
---
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title: Migrating from Libreboot where GbE size differs
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x-toc-enable: true
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...
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On most/all Dell systems, 8KB GbE regions are used in Libreboot, but
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the Canoeboot setup doesn't modify the GbE region size, instead leaving
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the usual default of 16KB in place.
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Because of this, since the ME region is next to the GbE region, if you
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were to flash a Canoeboot IFD once you already flashed Libreboot, you
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would, by virtue of the IFD's partition/region layout, overwrite the
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first 8KB of the ME region, thus bricking the machine until you correct it.
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Therefore, if you are migrating from Libreboot to Canoeboot on a Dell system,
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or indeed any system in fact, please check the size of the GbE region in
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Canoeboot's version. If the Canoeboot version is 16KB, which it is on most
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Dell systems, then do not overwrite the IFD region.
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In other words, please do:
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```
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flashprog -p PROGRAMMER --ifd -i bios -w canoeboot.rom
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```
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Please *only* flash the BIOS region, if you already have Libreboot and are
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migrating from Libreboot to Canoeboot. If you're migrating from *factory
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firmware* to Canoeboot, then you can also overwrite the IFD and GbE regions.
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If you still want to modify the GbE region, when migrating from Libreboot, you
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can, but you can do it manually; see [nvmutil documentation](nvmutil.md).
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These rules *still apply* when re-flashing over an existing Canoeboot
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installation, if the initial installation was *also* a migration from
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Libreboot.
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This is also true if switching to Canoeboot from vendor BIOS, but then
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changing to Libreboot later on and migrating back to Canoeboot.
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Libreboot shrinks the ME and GbE regions, and enlarges the BIOS region,
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auto-downloading and inserting Intel ME at build time. By contrast, Canoeboot
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cannot (by its policy) handle such files, so you leave the original Intel ME
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firmware intact and only flash the other regions, but rely on the HAP bit in
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the IFD to still disable Intel ME during early bringup.
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More about this is covered in [another guide](ivy_has_common.md).
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