skiboot v6.6 was released on Wednesday April 22nd 2020. It is the first release of skiboot 6.6 series, which becomes the new stable release following the skiboot-6.5 release, first released August 16th 2019.

There hasn’t been a skiboot release in a while and this release doesn’t contain a huge number of new features for users, just a lot of bug fixes, and additional platform support. The next release should be a little more lively with a number of internal refactorings and new features on the way.

New features

  • Skiboot is now dual licensed as Apache 2.0 -OR- GPLv2+

    There are some files still licensed Apache 2.0 only due to contributions that we are unable to change the license of, but they are the minority.

  • Skiboot can now be built as little endian, thanks to Team Nick.

    Doing so requires building with: make LITTLE_ENDIAN=1

  • OpenCAPI reset support

    This is to allow FPGA-based OpenCAPI devices to be re-flashed with a new device image, then reset to activate the new image. Although it is based on top of the existing PCI Hotplug support it does require some OS changes to function.


    These OPAL calls provide the OS with a means for controlling per-PHB settings. Currently this allows the OS to enable or disable the the “Global MMIO EEH Disable” and “4GTE” settings which are available on Power9 / PHB4. See the PHB specification for more details.

Removed features

  • Fast-reboot is now disabled by default.

    Fast-reboot will continue to be supported, but as an opt-in feature rather than the default. From the commit (ee07f2c68160) message:

    This has two user visible changes:
    1. Full reboot is now the default. In order to get fast-reboot as the
       default the nvram option needs to be set:
            nvram -p ibm,skiboot --update-config fast-reset=1
    2. The nvram option to force a fast-reboot even when some part of
       skiboot has called disable_fast_reboot() has changed from
       'fast-reset=im-feeling-lucky' to 'force-fast-reset=1' because
       it's impossible to actually use that 'feature' if fast-reboot is
       off by default.
            nvram -p ibm,skiboot --update-config force-fast-reset=1