This one has been a long time coming.

We have coreboot available now for the AMD StarBook Mk VI. Not "we got to the splash screen once and decided to call it done", but an actual usable beta with working WiFi, working S3, firmware updates, and a sane path back to stock if you want out.

And honestly, getting here was far more annoying than it should have been.

What is available?

Right now this is for:

- StarBook Mk VI AMD
- SKU `B6-A`
- Ryzen 7 5800U

It is available as a beta, and the supported path is:

1. get onto AMI `26.04`
2. switch to coreboot with the updater
3. if you want, switch back again with the updater

So this is not a one-way jump.

 

Why this took so long?

AMD support in this area is still a bit of a mess.

Part of the problem is the usual one: a lot of the platform behaviour lives in places you do not really want it to, and the documentation is not exactly overflowing with useful detail. Once you get into AMD platform firmware bring-up, you rapidly stop having the sort of clear, obvious path you get on paper. You get a lot of "why is that different", "why does AMI do that", and "why does changing this one thing fix WiFi but break resume".

That was basically the story here.

The original board work for Cezanne on our side goes back a while, but this recent push was where it actually turned into something shippable. Looking back through the branch and reflog trail, it is basically a record of us repeatedly finding out that one more thing was just a little bit broken:

- old board-add work from 2022 that needed dragging forward into something modern
- the `26.04_amd`, `26.04_amd2`, `cezanne_extra_debug`, `cezanne_patches`, `local/cezanne-working-coreboot` mess while we worked out what actually mattered
- a separate firmware trail where the story was basically "get the platform behaving properly, but without murdering S3 or WiFi"
- multiple debug and cleanup branches just to get GPIOs, HDA, CFR, SATA detection, and ACPI into a state that was not embarrassing

None of that is glamorous, but that is the work.

 

The fun parts

Some highlights:

- WiFi worked on one side, S3 worked on another, and naturally they were not the same side
- we had to pull parts of the platform behaviour back toward what AMI was doing in the bits that mattered, without cargo-culting random junk we did not need
- one of the first "fixes" for the boot countdown turned out to be wrong, because the problem was not the gate we thought it was, it was the non-HiDPI renderer path
- firmware capsules on AMD turned into another small side quest because the in-RAM path was not surviving reset cleanly, so we ended up wiring in capsule-on-disk support properly
- the updater path had to be tightened up so users could switch to coreboot and back without doing anything stupid halfway through the flash sequence

That is before getting into the usual AMD platform nonsense where you spend far too much time comparing behaviour against AMI because the docs are either thin, wrong, or missing the part you actually need.

 

What actually works now?

The current beta is in a good place:

- WiFi works
- S3 works
- touchpad works properly
- audio is sorted
- GPIO setup is cleaned up properly rather than being the usual minimum viable pile
- the firmware setup side is on the current EDK2 work, not some old half-broken menu flow
- capsule update support works from the coreboot side as well

Just as importantly, the update path is not hand-wavy.

You can:

1. update to AMI `26.04`
2. switch to coreboot with:

curl -fsSL <firmware-updater-url> | bash -s -- --coreboot-switch

3. switch back to the standard AMI firmware with:

curl -fsSL <firmware-updater-url> | bash -s -- --reinstall

We tested that path properly, end to end, not just by throwing images around manually and hoping for the best.

 

How to use it?

1. Check what you are running:

cat /sys/class/dmi/id/bios_vendor
cat /sys/class/dmi/id/bios_version

Expected values:

- AMI path: `American Megatrends International, LLC.` and `26.04`
- coreboot path: `coreboot` and `26.04`

2. If you are not already on AMI `26.04`, update to that first:

curl -fsSL <firmware-updater-url> | bash

Then re-check:

cat /sys/class/dmi/id/bios_version

3. Switch to the coreboot beta:

curl -fsSL <firmware-updater-url> | bash -s -- --coreboot-switch

This is only allowed on `B6-A`, and only from AMI `26.04`.

When it finishes, the updater will shut the machine down automatically.
After shutdown:

- disconnect the charger
- wait about 12 seconds until the LEDs flicker
- power it back on

4. Verify you are on coreboot:

cat /sys/class/dmi/id/bios_vendor
cat /sys/class/dmi/id/bios_version

Expected:

- `coreboot`
- `26.04`

5. Switch back to the normal BIOS:

curl -fsSL <firmware-updater-url> | bash -s -- --reinstall

That reflashes the normal `B6-A.bios` image and shuts the machine down automatically when complete.

6. Verify you are back on AMI:

cat /sys/class/dmi/id/bios_vendor
cat /sys/class/dmi/id/bios_version

Expected:

- `American Megatrends International, LLC.`
- `26.04`

 

Why this release matters?

The obvious bit is that AMD StarBook owners can now actually run coreboot.

The less obvious bit is that this gives us a real base to keep building on. The hard part with firmware is usually not getting *something* to boot. The hard part is getting it to the point where you can stop treating it like a lab experiment.

That is where this is now.

It is still a beta, because that is the honest label. But it is a beta in the sense of "we want broader real-world coverage", not "good luck, tell us what exploded".

 

The usual AMD rant

It would be nice if doing firmware on modern AMD laptops involved less archaeology.

There is still too much "compare against AMI and infer intent", too much "this one bit moved and now resume is dead", and too much time wasted because the official documentation is either sparse or does not answer the question you actually have. None of that is unique to this project, but it absolutely showed up here.

So yes, this took longer than any of us would have liked.

But the end result is real: coreboot for the AMD StarBook is now available.

 

What's next?

The beta is out there now, which means the next steps are the sensible ones:

- get feedback from real users
- tighten the remaining rough edges
- upstream as much of the coreboot work as we can
- keep improving the firmware stack instead of freezing it in place now that it basically works

If you have been waiting for coreboot on the AMD StarBook, you can stop waiting.

Byte Mk I, the Cezanne mini PC sibling, should follow shortly.

After that, work starts on StarFighter.