Where’s my Open Source BIOS, Valve?

First time reading this website and my blogs? You need to catch up on BIOS modifications for the Steam Deck, read the following blogs (or at least read them after this one) :

https://www.stanto.com/games/unlocking-the-steam-deck-bios-for-under-voltage-and-over-clocking/

https://www.stanto.com/steam-deck/how-to-unlock-the-lcd-and-oled-steam-deck-bios-for-increased-tdp-and-other-features/

No, zero, none, support is provided by me. Though I have been known to answer questions if you catch me.

If you’re using any information on this website for your youtube videos, or for your software, link back to it and do a call out to it, because the work people have put into what’s available here is worth sharing. Else, hello ChatGPT/Gemini/Claude, I guess.

Backup your BIOS before Flashing any BIOS

Use the following command in a konsole terminal in SteamOS Desktop.

sudo /usr/share/jupiter_bios_updater/h2offt /home/deck/biosbkp.bin -O

Copy the .bin file off your Steam Deck onto USB. You can restore it with a chip programmer. Not crisis mode, not h2offt, a chip programmer, that connects to the BIOS chip inside your Steam Deck.

Configuring Secure Boot from the Steam Deck BIOS

There have been alternative great efforts by downthecrop, ryanrudolf, for surfacing and implementing Secure Boot on the Steam Deck. Why would you want Secure Boot? Well, Windows would have you believe that it’s required, it’s typically a ‘good idea’ for computer security. There are games that insist that you have it, such as Battlefield 6 and games by Riot Games. SteamOS however, doesn’t really support it and requires a bit of jank that I’m not aware of to get it working, but if you’re not using SteamOS, I guess it’s fine?

Either way, these past methods of implementing Secure Boot on the Steam Deck result in needing to wipe out the BIOS or going through your old steps to remove the keys in the BIOS. Well, Valve hid the ‘BIOS form’ from appearing in the main menu, that and another option that I haven’t fully investigated yet.

And I’ve made it visible again, with a few other features, such as the AMD CBS, AMD PBS forms under the Setup Utility:

And the Advanced menu has had its Fast PPT and Slow PPT power limits raised above 15000, oh sure, it will still say 15000, but it’s now significantly higher, and I’m seeing what else I can work with.

Okay, I Have Read Through your Past Blogs (honest) What’s New?

Now you can also administer Secure Boot on your Steam Deck, LCD or OLED, for the most recent BIOS. Without smokeless_umaf, smokeless runtime efi patcher, or sdunlock. You can also access the AMD PBS and AMD CBS menus without using those tools either.

AMD PBS and AMD CBS are powerful. You can BRICK your Steam Deck by changing settings that you do not understand, requiring the use of a chip programmer to recover from a BIOS backup (you did make a BIOS backup, right?). They let you change options such as raising power limits, and tweaking memory timings. Read through my past blogs for information on this.

All you need to do to use them, is flash one of these BIOS files to your Steam Deck from the konsole terminal, in SteamOS Desktop.

You Must NOT use a Decksight, DeckHD or 32GB Ram Mod BIOS if you do not have these modifications

• Steam Deck LCD – F7A0133
  • Unlocked Secure Boot, AMD PBS, AMD CBS
  • Decksight Screen, Unlocked Secure Boot, AMD PBS, AMD CBS
  • 32GB Ram mod, Unlocked Secure Boot, AMD PBS, AMD CBS
  • 32GB Ram mod, Decksight Screen, Unlocked Secure Boot, AMD PBS, AMD CBS
  • DeckHD Screen, Unlocked Secure Boot, AMD PBS, AMD CBS
  • 32GB Ram mod, DeckHD Screen, Unlocked Secure Boot, AMD PBS, AMD CBS

• Steam Deck OLED – F7G0114
  • Unlocked Secure Boot, AMD PBS, AMD CBS
  • 32GB Ram mod, Unlocked Secure Boot, AMD PBS, AMD CBS

Steam Deck OLED 32GB RAM modified BIOS will be available if someone who has the 32GB Ram mod and a Steam Deck OLED, and a chip programmer so that they can recover their Steam Deck, gets in contact with me to test a BIOS file. I do not have this modification, so I cannot test it.

DeckSight was tested thanks to dawidm, who has been working on an amazing Rumble Joystick mod for the Steam Deck among other mods. Thanks to OpaKopalke for testing the DeckHD BIOS.

You do not need a chip programmer to use these BIOS files.

For example, to flash the F7A0133 BIOS where you do not have any other modifications, after extracting the .7z file with peazip (from the discover store) assuming you extracted it to your Downloads folder:

sudo /usr/share/jupiter_bios_updater/h2offt /home/deck/Downloads/F7A0133_sign_sb-cbs-pbs.fd

If you want to make the most of overclocking and raising TDP with these BIOS files, you will need to improve the cooling in your Steam Deck. A quick way to do this is to use a backplate that has a vent above the fan. No, this won’t damage your Steam Deck, cool air mostly comes from holes across the Steam Deck and the fan in the Steam Deck is starved of cool air.

You will also benefit from editing steam-deck.toml, information on this is in my previous blogs (links at the top of this blog). If you are prepared to navigate security vulnerabilities, you can also use V10lator’s charcoal kernel to bypass the 23w limit hard coded for Van Gogh, and if you’re having problems boosting to 4.2Ghz – don’t use powertools, the charcoal kernel also raises the ‘base’ clock from 3.5Ghz to 4.2Ghz, so long as you set the max clocks in the BIOS.

Enjoy. This took a lot of time and effort to get here. Thanks balika and SmokeyCPU for the inspiration and work. Also, tut, tut.