Yesterday, we reported that Google may be bringing Windows 10 support to multiple Chromebooks through a project called ‘Campfire’. However, new evidence has come to light this morning suggesting that the Pixelbook may be the only currently available Chromebook to join Windows around the campfire.

To explain this, we have to get a bit technical with the inner workings of Chrome OS and how Campfire is intended to operate. So buckle up — it’s going to be a bumpy ride.

All modern, Intel-based Chromebooks, since the Chromebook Pixel, come with a built-in “Legacy Boot Mode”, intended for letting enthusiasts boot Linux. Legacy Boot Mode works by loading a traditional computer BIOS, (the open source SeaBIOS), that’s flashed directly to the system as part of the device’s firmware, in a section called “RW_LEGACY”.

To make Campfire work correctly, Chrome OS needs to automatically update RW_LEGACY, and until a July firmware change this was not possible. With this change, updates will happen automatically if a certain file called “cros_allow_auto_update” is found in a read-only filesystem. However, this update and the special file will only arrive on devices released afterward, or those that receive a major firmware update.

If things were left in that state, the Pixelbook, Google’s premier Chromebook, would not receive Campfire support. This was obviously not going to be the case, as all evidence we have seen thus far points to the Pixelbook (internally called Eve) being the test mule for Campfire, including branches labeled “eve-campfire“.

A new change was proposed this morning related to the RW_LEGACY update process, and Chromium developers discussed where the change should be implemented, if at all. In this discussion an interesting comment appears, emphasis mine:

Considering that this is and should forever remain an Eve-specific thing, I think it would be better to attach the custom updater higher (e.g. other boards should never even have a reason to “preserve” anything here so this call is useless). We will still need to change more about the Eve legacy update flow anyway to deal with the fact that it was shipped before we started putting cros_allow_auto_update files into CBFS, so I think we’ll end up needing to overwrite all of check_and_update_legacy() anyway. Why not do that right now? I think keeping stuff cleaner for all future boards weighs higher than the little bit of code duplication this would net us for this one board.

It’s certainly not definitive evidence, but it reads to me like the Pixelbook may be the only Chromebook on the market today to get the option to boot Windows. This should come as no surprise, though, as the overwhelming majority of today’s Chromebooks do not meet the minimum 40GB of storage space required to install Chrome OS and Windows.

Additionally, Microsoft has a rigorous hardware testing process before allowing a device to market itself as being able to run Windows 10. (This process has already begun for Pixelbook, as we noted in June). Most manufacturers probably would not put in the effort to introduce such an in-depth new feature to an existing device, instead likely opting to create and market a new one.

9to5Google’s Take

Windows 10 support would make Chromebooks the most versatile devices on the market, adding the ability to dual-boot and run Windows-only software to the current mix of Chrome OS, Android, and Linux app support. It’s too early to tell at this point if this will be a Pixel-exclusive feature, but here’s hoping other manufacturers will gather round the campfire.

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