Firmware specialist 3mdeb has released Dasharo v0.9.0 for the MSI PRO B850-P WIFI motherboard, bringing the first published open-source firmware stack to a modern AMD AM5 desktop platform. Tested with Windows 11 25H2 and Ubuntu 26.04 LTS, the release combines coreboot, AMD’s openSIL silicon-initialization code, and an EDK II UEFI payload — but it supports only a narrow slice of Ryzen 8000-series APUs.

What’s New in Dasharo v0.9.0

The firmware, announced on July 30, 2026, is a major departure from the opaque, proprietary BIOS typically shipped with AM5 boards. At its heart, Dasharo replaces AMD’s closed-source AGESA initialization stack with openSIL (Open-Source Silicon Initialization Library) and swaps the conventional UEFI framework for coreboot. The result is a firmware image where 79.1% less code is proprietary, according to 3mdeb’s comparison against MSI firmware version E7E56AMSI.2A92.

Crucially, this is not a fully open-source system. AMD’s Platform Security Processor (PSP) firmware remains a required binary blob, along with certain device firmware and drivers. But the core platform initialization code — the part responsible for bringing the processor and chipset to life — is now auditable source code. That’s a first for any off-the-shelf AM5 motherboard.

Windows 11 Compatibility at a Glance

For Windows users, the big story is that Dasharo v0.9.0 passes the bar for a modern, secure UEFI boot. The firmware supports:

  • UEFI boot with Secure Boot
  • AMD fTPM (firmware TPM 2.0) running inside the PSP
  • TPM Measured Boot
  • Capsule-on-disk firmware updates

Because fTPM is functional, features like BitLocker drive encryption, Windows Hello biometrics, and enterprise device attestation work out of the box. Secure Boot keys are pre-provisioned, so a fresh Windows 11 installation on this board shouldn’t require any special gymnastics. Measured Boot allows hypervisors and security software to verify the boot chain, a must for enterprise deployments.

The CPU Support Gap: Not Every AM5 Chip Works

Here’s where excitement meets reality. Dasharo v0.9.0 works exclusively with AMD Phoenix-based Zen 4 desktop processors — in practice, the Ryzen 8000G-series APUs. 3mdeb validated the release with a Ryzen 5 8600G and says the Ryzen 7 8700G is the highest‑end supported chip in this branch. Standard Ryzen 7000, Ryzen 9000, and any X3D model are not supported.

The limitation isn’t a hardware incompatibility with the B850 socket. It’s a software constraint: the phoenix_poc branch of AMD’s openSIL doesn’t yet cover other Zen 4 or Zen 5 silicon. You could physically install a Ryzen 9 9950X in the MSI PRO B850-P WIFI, but Dasharo wouldn’t boot it. This is a developer preview, not a drop‑in replacement for MSI’s Click BIOS across the AM5 lineup.

Why Open Firmware Matters for Windows Users

Transparency. That’s the one‑word answer. For decades, the firmware that initializes your PC’s hardware has been a black box — millions of lines of code that even operating system vendors can’t fully audit. When a UEFI vulnerability like LogoFAIL or BlackLotus surfaces, defenders are often left scrambling because they can’t easily see what’s happening below the OS.

Open-source firmware changes that equation. Security researchers and IT teams can inspect the boot flow, verify that no malicious hooks exist, and contribute fixes directly. For organizations subject to compliance standards like NIST SP 800‑193, the ability to audit platform firmware is invaluable. 3mdeb also baked in SMM flash‑write protection via AMD ROM Armor 3, a hardware‑enforced lock that prevents runtime code from tampering with the firmware image — something many retail UEFI implementations still don’t offer.

A Brief History of Open-Source x86 Firmware

Open-source firmware for x86 isn’t new. Coreboot has been around since 1999, powering Chromebooks and niche server boards. But it’s been largely absent from consumer desktop hardware, especially on AMD platforms. The reason: AMD’s reliance on the closed-source AGESA (AMD Generic Encapsulated Software Architecture) for processor and chipset initialization.

That changed in 2023 when AMD announced openSIL, a project to replace AGESA with vendor‑neutral, open-source silicon initialization code. The original roadmap targeted server CPUs (EPYC) first, with client support arriving later. Dasharo v0.9.0 is the first tangible proof that openSIL can boot a modern client platform — and importantly, that it can do so with Windows, not just Linux.

The EDK II UEFI payload, maintained by TianoCore, provides the standard UEFI interfaces that Windows expects. Together with coreboot’s hardware initialization and openSIL’s processor setup, the stack delivers a fully functional UEFI environment that’s indistinguishable to the OS from a conventional BIOS — except for being mostly open.

Known Limitations and What Still Needs Polish

Dasharo v0.9.0 is an early build, and the version number (0.9.0) hints that it’s not yet a polished release. 3mdeb has documented four current limitations:

  • Staged UEFI capsule updates don’t survive a system reset. You can apply an update from within Windows, but it won’t persist after reboot. Only immediate capsule-on-disk updates work.
  • The board may not reliably restore its power state after a full power‑off. If you shut down with the PSU switched off, it might not turn back on correctly.
  • Ubuntu 26.04 can hang intermittently when serial‑console redirection is enabled. This is a Linux‑specific issue, so Windows users aren’t affected.
  • The onboard Wi‑Fi adapter sometimes disappears until you clear the CMOS. Interestingly, 3mdeb says the same behavior occurs under MSI’s own firmware.

There are also deeper architectural constraints. The current coreboot port can’t modify AMD’s APCB (AMD Platform Customization Block) configuration data. That means you can’t tweak CPU parameters, memory subtimings, or overclocking settings from the firmware level. Enthusiasts who rely on Precision Boost Overdrive or Curve Optimizer will find Dasharo too restrictive for now.

Should You Try It? A Practical Guide

If the following checklist describes your system, you could technically install Dasharo today:

  • You own an MSI PRO B850-P WIFI motherboard (exact model, no substitutes)
  • You’re running a Ryzen 8000G‑series APU (8600G or 8700G)
  • You’re comfortable with low‑level flashing tools and accepting the risk of bricking your board

For everyone else, this release is a proof of concept — an exciting one, but not a daily driver. Even if you meet the hardware requirements, the missing staged‑update support means maintaining a secure firmware will be manual. And the lingering power‑state and Wi‑Fi quirks are the kind of papercuts that turn an interesting experiment into a frustrating daily experience.

That said, there is a real use case for this firmware today. Organizations building air‑gapped or highly audited Windows 11 appliances could leverage the SBOM‑grade transparency of Dasharo on a specific, known‑good hardware configuration. 3mdeb’s commercial support might make this viable for niche deployments.

What’s Next for Dasharo on AMD

3mdeb’s immediate to‑do list is clear: upstream the Phoenix and MSI PRO B850‑P code to coreboot, contribute its openSIL changes back to AMD, and squash the known bugs. Longer term, the team wants to add support for pre‑boot DMA protection, suspend‑to‑idle (modern standby), and firmware‑update reliability.

The bigger question is when AMD will expand its openSIL coverage beyond Phoenix. Until openSIL officially supports the full Zen 4 and Zen 5 desktop lineups, Dasharo will remain a curiosity for AM5 enthusiasts rather than a movement. AMD’s Zen 6 platform, expected in 2027, might be the real watershed if openSIL becomes the default initialization path — a possibility hinted at by recent reports that AMD is porting openSIL to Zen 5 motherboards in preparation for that transition.

For now, Dasharo v0.9.0 is a landmark: the first time a modern AMD desktop platform can boot Windows with the bulk of its firmware in the light. It’s a foundation, not a finished product, but it proves the model works. The next 12 months will show whether AMD and the open‑source community can turn this proof into something every AM5 owner can use.