It took a few days, but here comes the Atmosphère custom firmware update , even if it is still in pre-release. Usually, these versions do not undergo major changes and become stable within a few days.

The update still introduces basic support for firmware 20.0.0, allowing the console to boot and Atmosphère to function , although not all modules have been fully updated to reflect the latest changes.

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For the end user, there are no obvious changes. However, some internal changes are significant, especially in terms of memory management.

Due to a change Nintendo introduced in firmware 20.0.0, there is now a reduction of approximately 10 MB of memory available for custom system modules.

In practice, only 14 MB can be subtracted from the applet memory pool, compared to the 40 MB previously available.

To overcome this limitation, the memory used by has been reduced by 20 MB ams.mitm, and at the same time a new support module, called “memlet”, has been introduced, which allows to temporarily steal memory during the generation of the romfs file.

Despite these optimizations, some user modifications – particularly those that replace very large numbers of files in games like The Legend of Zelda: Tears of the Kingdom – may no longer be compatible.

In those cases, the system will return a “Data abort (0x101)” error when starting the game. If this happens, SciresM , invites you to send the error report via Discord, although he admits that some issues may not be solvable. The choices made are the result of a necessary compromise to ensure general stability.

In addition, the exosphère , mesosphère , loader , pm and erpt modules have been updated to reflect the behavior of their official counterparts.

ncm also received a partial update. Atmosphère is now compiled with GCC 15 and the latest versions of devkitA64 and devkitARM.

Major improvements have also been made to the dmnt cheat engine , with new instructions and advanced features documented thanks to the contribution of tomvita.

Finally, general optimizations to system stability have been introduced, to offer a smoother and more reliable user experience.

Changelog

Be sure to update fusee when you upgrade to 1.9.0. fusee-primary no longer exists and will no longer work.

Note: Atmosphère 1.9.0 is currently in pre-release and may encounter issues that will need to be resolved before the full release.

If bugs are reported during the pre-release of Atmosphère , they will be fixed and the build will be updated. Version 1.9.0 will become stable after a short period of time with no critical bug reports.

Thanks to the @switchbrew team , Atmosphère 1.9.0 includes hbl 2.4.4 and hbmenu 3.6.0.

Added basic support for version 20.0.0.
- The console should boot correctly and Atmosphère should be fully functional. However, not all modules have been fully updated to reflect the latest changes.
  - There should be no visible differences to the user, but this will be addressed in a future Atmosphère update.
  - The same action item from version 18.0.0 is still pending, and in my heart I believe it will be fixed sooner or later. Someone told me they are working on it.
  - There are no more (as far as I know) pending issues related to version 19.0.0.
- Note : Due to changes made to Nintendo software in version 20.0.0, there is approximately 10 MB less memory available for custom system modules.
  - We can now subtract a maximum of 14 MB from the applet pool, up from 40 MB previously.
  - To compensate for this reduction, heap usage ams.mitmhas been reduced by 20 MB.
    - To facilitate this, a new helper module ( ) has been added memlet, which allows you to temporarily steal memory during the romfs.
    - Hopefully this will cause few problems, but it is possible that user-created mods that replace extremely large numbers of files in The Legend of Zelda: Tears of the Kingdom may no longer work.
      - If this issue occurs, you will see “Data abort (0x101)” when launching the game with mods active.
      - In that case, please contact SciresM on Discord to send the binary error report. However, some issues may not be fixable.
      - I sincerely apologize if the problem cannot be resolved, but I have been forced to make difficult decisions and I believe this is the best compromise possible.
- exosphèrehas been updated to reflect the latest behavior of the official secure monitor.
- mesosphèrehas been updated to reflect the latest behavior of the official kernel.
- loaderhas been updated to reflect the latest behavior of the official system.
- pmhas been updated to reflect the latest behavior of the official system.
- ncmhas been partially updated to reflect the latest behavior of the official system.
- erpthas been updated to reflect the latest behavior of the official system.
Atmosphère has been updated to use GCC 15/newlib (latest versions of devkitA64/devkitARM).
Numerous improvements have been made to the cheat engine dmnt.
- New instructions have been added, and existing ones have been updated to improve or extend their functionality.
- For more details, please refer to the documentation – thanks to @tomvita !
General system stability improvements to optimize user experience.