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Choose Steam in the launcher's library. The first time, guided screens in the setup's style say what will happen
and keep saying it until you are signed in:
Download. Steam's installer comes from Valve's servers and is checked before it runs.
Install. About half a minute when MihawkOS is already set up.
First start. Steam updates itself, about five minutes. A still screen is normal: the guide shows the download
and the time.
Sign in once. Open the Steam app on your phone, tap the shield and scan the code. MihawkOS closes Steam as soon
as your sign-in is saved.
Big Picture. From then on, Steam opens straight into Big Picture, made for the controller.
Steam games start in about half the time. Steam's own file check is skipped, and a game's file reads, opens and
look-ups are much cheaper. A 2D game launched from its library entry reached steady play in 66 seconds, down from 120.
Choose the controller your games see.Settings → Controller: Xbox 360 (the default), Xbox One or DualSense. Steam no longer sees your pad twice, and its button glyphs match your choice.
Something went wrong? No internet, the console's clock, a stalled update, a cancelled sign-in: the guide says
which, with Try again or Back.
Big Picture, smooth
Big Picture used to stutter. On a standard PS5 (firmware 13.60) at 120 Hz, the frames that took longer than 20 ms:
In Big Picture
Before
Now
The first minute
79
16
Scrolling the library
162 (worst frame 190 ms)
7 (worst frame 53 ms)
The menus
74
24
How: on firmware 12.00 and later, Steam's built-in browser now runs as separate processes. That costs memory:
Steam's helpers use 429 MiB instead of 320. With a game started from Big Picture, the console's shared memory
peaked at 1,123 MiB and the game held 60 frames a second.
On the PS5 Pro (firmware 10.01), which has less memory to spare, the browser stays one process with a larger code
budget. Frames over 20 ms while scrolling fell from about 125 to 57 (worst frame 51 ms) and in the first minute
from 140 to 109; the menus are unchanged on the Pro (about 76).
MihawkOS is not affiliated with Valve. Nothing of Valve's is in this release.
Your browser companion
While the launcher is on screen, MihawkOS serves a page on port 6767. Scan the QR code under the library, or in Settings → Web UI, with your phone, or type http://<PS5 address>:6767 on a computer on the same network.
My games: every game with its picture and whether it is ready to play. Give one its own Game Mode and controller.
Add a game: choose its folder on your computer, copy it to the console (a stopped copy carries on), and set it up
with its program suggested.
Picture and details: look the game up in the Steam store, or use your own picture.
Home screen: a tile that opens MihawkOS straight into one game. It appears a few seconds after MihawkOS closes.
Saves: download a game's saves as a ZIP, and put them back.
Settings and Help: the launcher's settings, theme and music, and a bug report with every address masked.
The page uses the guided setup's ten languages and stops when a game starts, so it holds no memory while you play.
Use it on a trusted network, and do not forward port 6767 to the internet.
A first launch in your language
Install over FTP. Beside the USB drive, the setup's How to install now offers FTP: copy every file inside
the release's mihawkos folder to /data/ps5proton/install, then Check files and Install.
Ten languages: English (US), Français, Español, Deutsch, Italiano, Русский, 简体中文, 日本語, Português (Brasil),
and now Polski.
The Frutiger Aero look, on the loading screen before a game too, and the Bubble Earth wallpaper on the Mihawk
11 desktop.
USB keyboard and mouse load first, before anything else starts. A tester's console where neither worked now
reads both.
More room for your games
Every Windows program but the desktop's runs in a helper, and all helpers share one small memory pool with the
console's own processes. This alpha leaves more of it for your game:
A game can run inside MihawkOS itself, off the shared pool. Its entry names it
(WINE_PS5_TITLE_PROCESS=<program>.exe). This works for 64-bit games.
Each helper's converted code has a budget: 64 MiB to start, raised only when code it let go keeps coming back,
for games, Steam and the game launchers alike. Steam's web helper went from 234-250 MiB to 173-193 MiB, and every
helper starts about 8 MiB lighter.
A memory notice that knows your console. "The PS5's memory is getting full" now appears where each firmware
starts to swap, not at one figure for all.
One loader on every firmware
Testers on firmware 11.00, 12.40 and 13.x saw MihawkOS stop before the desktop with "errno 92". The cause: a helper
asked the console to load Wine's modules, and on those consoles the jailbreak tools could not load them inside a
helper. On 12.40 the console's own log showed it.
Helpers now load Wine's modules with MihawkOS's own loader, on every firmware, so they no longer depend on the
jailbreak's support for fake-signed programs. This removes the cause testers reported.
Standard PS5 on 13.60: the full test battery passed, 102 of 102, with every helper on the new loader.
PS5 Pro on 10.01, whose helpers used the console's loader until now: Steam ran with all its helpers on the new
loader. It costs about 20 MiB more across Steam's helpers.
No tester has confirmed it on firmware 11.00 yet, nor on other firmwares we have no console for. If you are on
11.00, 12.40 or another untested firmware, your report is welcome.
Fixes
Wine's own test suite now runs on the console, each test file compared with the same file on a PC: 1,337 of 1,708
test files match. What it found was fixed for every program:
Files keep their Windows attributes (hidden, read-only, system), though the PS5's disk has none.
Symbolic links and junctions work, and so does a directory's reparse tag.
Programs hear about folder changes at once.
Each 4 KiB page keeps its own protection, on a console whose pages are 16 KiB.
Programs can debug the programs they start.
A 32-bit video demuxer no longer reads memory it may only run.
Encryption without a starting vector begins from zeros, as Windows does.
Crash dumps of a running program work.
MihawkOS keeps running when one program misbehaves: a server that cannot reach a program, a display scale of 0.
Fonts: Chinese text in Windows programs draws in its right weight, and games that bring their own fonts can use
them.
OpenGL: swapping buffers with no current context, copying between windows, and a context deleted while another
thread still uses it are all answered as Windows answers them.
Also fixed, found with real programs:
Programs that use privileged processor instructions (SGDT, SIDT, SLDT, SMSW, STR) in their start-up code no
longer crash on the PS5: MihawkOS answers them the way Linux does on a PC. A Steam game's start-up code showed the
crash.
Vulkan programs that ask for "immediate" or "mailbox" presentation now get a window instead of a refusal, and a
Vulkan window reports its own drawing area correctly.
Played on the console
This release's build, the full test battery of 104 cases:
Standard PS5, firmware 13.60: 104 of 104 (merge-bp-gate-base-2026-10-27-01, 31 minutes).
The combined tree before today's later fixes: 102 of 102 on both consoles (int-gate-base-2026-10-27-01, gate-integration-1027-pro-01). On both, Wine's OpenGL test for the new Windows Zink passed in its 64-bit and 32-bit
builds, 10,525 tests each.
On the way there, on a PS5 Pro (firmware 10.01) and a standard PS5 (firmware 13.40, then 13.60), from this series'
development builds:
What
How it went
Steam
Standard PS5: installed, signed in with the phone and opened in Big Picture from a new prefix, twice. PS5 Pro: installed in 22-27 seconds; its sign-in window used at most 589 of the 870 MiB the console allows.
Steam's start
PS5 Pro: a 2D game steady at 60 frames a second 66 seconds after its launch (was 120).
The controller choice
Standard PS5: each of Xbox 360, Xbox One and DualSense reached programs as chosen, and Big Picture showed the matching glyphs.
The guide
Standard PS5: its 5 launcher pages and 5 session screens drawn in all ten languages.
Smooth Big Picture
Standard PS5 13.60 at 120 Hz: frames over 20 ms fell from 79 to 16 in the first minute, from 162 to 7 while scrolling, and from 74 to 24 in the menus. A game started from Big Picture held 60 frames a second. PS5 Pro (one process, larger code budget): scrolling from about 125 to 57, first minute from 140 to 109, menus unchanged.
The WebUI
Standard PS5: used from a phone; a home-screen tile made, shown with its picture, and started.
FTP install
PS5 Pro: from Welcome through FTP to "You're all set", over a runtime already in place.
A game inside MihawkOS
Standard PS5: a large 3D game on Direct3D 12 at about 117 frames a second, its helpers at 59 MiB.
The code budget
Standard PS5, fresh boot: the same 3D game never needed a raise, and the 2D game through Steam held 60 frames a second.
MihawkOS's own loader
Standard PS5: in a full battery, all 410 helpers logged the new loader. PS5 Pro: in the combined tree's battery, all 430 did. On both, a program could still reserve 917 GiB of address space. PS5 Pro, Steam alone: Steam for 90 seconds with no crash, all 8 helpers on the new loader, 386 MiB across them against 366 MiB with the console's loader.
Keyboard and mouse
PS5 Pro: both load before the /data grant; a tester's PS5 on 13.60 reads both.
Not shown on the console: a first Steam download through the guide (the installer was already on the console); a
fresh 1.2 GB install over FTP; the WebUI's store look-up, a game's own Game Mode and controller from the page, and its
120 Hz setting, since their last fixes; MihawkOS's own loader on firmware 11.00, 12.40 or any firmware we have no console for; a game inside MihawkOS
on the PS5 Pro.
Known limits
Pipe memory runs out after very many program starts. Each boot has a fixed budget, and every program start uses
some that is never given back. When it runs out, MihawkOS says Restart the PS5. A restart is the only cure.
The PS5 Pro has less memory for Windows programs: its memory guard steps in at about 870 MiB, against about 1,800
MiB on the standard PS5. Steam and the tested games fit; a launcher with a heavy built-in browser can be closed by the
guard during its start.
Translations still need a native speaker's review. The Mihawk 11 desktop stays in English.
The per-boot setup is yours: your homebrew enabler, elfldr and websrv after every cold boot. Never use rest mode.
ShadowMountPlus 1.7beta4 on firmware 10.01: another homebrew may not start after MihawkOS closes; restart the PS5.
A new home-screen tile appears only after MihawkOS closes.
A game started in a brand-new prefix's first session did not get the DualSense. The guided setup ends that
session itself.
Some games stop at an error of their own at start-up, the same one they show under Proton on a PC.
Black screen after restoring Steam's window. If Steam's desktop window is minimized and restored, it can come
back 2 pixels larger than the screen, and MihawkOS shows a black screen while Steam keeps running (downloads go
on). Big Picture, which fills the screen exactly, isn't affected. Fixed for the next release.
Not supported: kernel drivers and anti-cheat. Rumble is not proven. The setup's Internet install is not available
in this release.
Installing or updating
File
Size
What it is
PS5_MihawkOS-v4.0.0-alpha-4-PPSA99170.zip
19.8 MB
The MihawkOS title: the PPSA99170 folder
PS5_MihawkOS-v4.0.0-alpha-4-usb-mihawkos.zip
520.5 MB
The Windows runtime: the mihawkos folder, for a USB drive or FTP
PS5_MihawkOS-v4.0.0-alpha-4-README.txt
1 KB
The install steps in short
PS5_MihawkOS-v4.0.0-alpha-4-SHA256SUMS
39 KB
The SHA-256 of every file in both folders: sha256sum -c checks a copy
PS5_MihawkOS-v4.0.0-alpha-4-zips.sha256
1 KB
The SHA-256 of the two zips
New install: copy PPSA99170 to /data/homebrew/, wait about 45 seconds, and open MihawkOS from the home screen.
The guided setup installs the runtime from a USB drive or over FTP. The README
has every step.
Updating from v3.0.0-alpha-3:
Back up your saves, for example from the WebUI's Saves page once this version is installed, or over FTP from /data/ps5proton/prefixes/mihawk/drive_c/users/Mihawk/.
Replace the PPSA99170 folder in /data/homebrew/ with the new one.
Install the new runtime: open MihawkOS, then Settings → Guided setup, and install from the new USB pieces or
over FTP. The launcher refuses games until the runtime matches this version.
Restart the PS5, load your payloads, and open MihawkOS.
Your prefix, your games in C:\Games, Steam and your settings are kept.
No games, saves, keys or firmware are supplied. Use only games and programs you have the right to run.
Source, licences and credits
Changes since v3.0.0-alpha-3. Release source: the
complete corresponding source is the repository at that tag, with every patch MihawkOS applies to an upstream project
and the build scripts that pin every other input by revision or SHA-256. MihawkOS is free software under the GNU
General Public License v3.0 or later; each component keeps its own licence, listed with its pin in NOTICE.md, and
every licence text ships with the binaries. New upstream inputs since alpha-3: GNU libmicrohttpd 1.0.10 for the WebUI
(LGPL-2.1-or-later), Nayuki's QR Code generator 1.8.0 (MIT), and the Noto Sans SC and JP faces for the Chinese and
Japanese screens (OFL-1.1).
Thank you to the testers who sent their logs from firmware 11.00, 12.40 and 13.x, which found errno 92; to the
tester whose patch brought the keyboard and mouse up first; to drakmor for ShadowMountPlus, which puts the
WebUI's tiles on the home screen; to mpereiraesaa for prospero-win and the Lapy daemon's port, with Arksama /
Team PHU; to the Wine, Proton, GE-Proton, DXVK, VKD3D-Proton and Mesa developers; and to the
PS5 homebrew scene. The WebUI and its tiles follow PS5_RetroArch's.
MihawkOS is an independent hobby project, not affiliated with, sponsored by or endorsed by Sony Interactive
Entertainment, Microsoft, Valve or any game publisher. PlayStation, PS5 and DualSense are trademarks of Sony
Interactive Entertainment Inc.; Windows is a trademark of Microsoft Corporation; Steam and Proton are trademarks of
Valve Corporation. You are responsible for having the right to the programs you run, and for whether modifying your
console is lawful where you live (LEGAL.md).
Smooth Steam Big Picture. Far fewer hitches when it opens, while you scroll and in its menus.
Steam, built in. Download, install and sign in once with your phone, guided all the way. After that, Big Picture opens from the launcher.
Your browser companion. Add games, find their art, make home-screen tiles, back up saves and change settings from your phone or computer.
Install over FTP, in ten languages. The guided setup takes the runtime over FTP too, and now speaks Polish.
More room for your games. Helpers use less of the console's shared memory, and a game can run inside MihawkOS itself.
Fixes found by Wine's own tests, run on the console and compared with a PC.
