4.14 Moving to the Yocto Project 2.6 Release

This section provides migration information for moving to the Yocto Project 2.6 Release from the prior release.

4.14.1 GCC 8.2 is Now Used by Default

The GNU Compiler Collection version 8.2 is now used by default for compilation. For more information on what has changed in the GCC 8.x release, see https://gcc.gnu.org/gcc-8/changes.html.

If you still need to compile with version 7.x, GCC 7.3 is also provided. You can select this version by setting the and can be selected by setting the GCCVERSION variable to “7.%” in your configuration.

4.14.2 Removed Recipes

The following recipes have been removed:

  • beecrypt: No longer needed since moving to RPM 4.

  • bigreqsproto: Replaced by xorgproto.

  • calibrateproto: Removed in favor of xinput.

  • compositeproto: Replaced by xorgproto.

  • damageproto: Replaced by xorgproto.

  • dmxproto: Replaced by xorgproto.

  • dri2proto: Replaced by xorgproto.

  • dri3proto: Replaced by xorgproto.

  • eee-acpi-scripts: Became obsolete.

  • fixesproto: Replaced by xorgproto.

  • fontsproto: Replaced by xorgproto.

  • fstests: Became obsolete.

  • gccmakedep: No longer used.

  • glproto: Replaced by xorgproto.

  • gnome-desktop3: No longer needed. This recipe has moved to meta-oe.

  • icon-naming-utils: No longer used since the Sato theme was removed in 2016.

  • inputproto: Replaced by xorgproto.

  • kbproto: Replaced by xorgproto.

  • libusb-compat: Became obsolete.

  • libuser: Became obsolete.

  • libnfsidmap: No longer an external requirement since nfs-utils 2.2.1. libnfsidmap is now integrated.

  • libxcalibrate: No longer needed with xinput

  • mktemp: Became obsolete. The mktemp command is provided by both busybox and coreutils.

  • ossp-uuid: Is not being maintained and has mostly been replaced by uuid.h in util-linux.

  • pax-utils: No longer needed. Previous QA tests that did use this recipe are now done at build time.

  • pcmciautils: Became obsolete.

  • pixz: No longer needed. xz now supports multi-threaded compression.

  • presentproto: Replaced by xorgproto.

  • randrproto: Replaced by xorgproto.

  • recordproto: Replaced by xorgproto.

  • renderproto: Replaced by xorgproto.

  • resourceproto: Replaced by xorgproto.

  • scrnsaverproto: Replaced by xorgproto.

  • trace-cmd: Became obsolete. perf replaced this recipe’s functionally.

  • videoproto: Replaced by xorgproto.

  • wireless-tools: Became obsolete. Superseded by iw.

  • xcmiscproto: Replaced by xorgproto.

  • xextproto: Replaced by xorgproto.

  • xf86dgaproto: Replaced by xorgproto.

  • xf86driproto: Replaced by xorgproto.

  • xf86miscproto: Replaced by xorgproto.

  • xf86-video-omapfb: Became obsolete. Use kernel modesetting driver instead.

  • xf86-video-omap: Became obsolete. Use kernel modesetting driver instead.

  • xf86vidmodeproto: Replaced by xorgproto.

  • xineramaproto: Replaced by xorgproto.

  • xproto: Replaced by xorgproto.

  • yasm: No longer needed since previous usages are now satisfied by nasm.

4.14.3 Packaging Changes

The following packaging changes have been made:

  • cmake: cmake.m4 and toolchain files have been moved to the main package.

  • iptables: The iptables modules have been split into separate packages.

  • alsa-lib: libasound is now in the main alsa-lib package instead of libasound.

  • glibc: libnss-db is now in its own package along with a /var/db/makedbs.sh script to update databases.

  • python and python3: The main package has been removed from the recipe. You must install specific packages or python-modules / python3-modules for everything.

  • systemtap: Moved systemtap-exporter into its own package.

4.14.4 XOrg Protocol dependencies

The *proto upstream repositories have been combined into one “xorgproto” repository. Thus, the corresponding recipes have also been combined into a single xorgproto recipe. Any recipes that depend upon the older *proto recipes need to be changed to depend on the newer xorgproto recipe instead.

For names of recipes removed because of this repository change, see the Removed Recipes section.

4.14.5 distutils and distutils3 Now Prevent Fetching Dependencies During the do_configure Task

Previously, it was possible for Python recipes that inherited the distutils and distutils3 classes to fetch code during the do_configure task to satisfy dependencies mentioned in setup.py if those dependencies were not provided in the sysroot (i.e. recipes providing the dependencies were missing from DEPENDS).


This change affects classes beyond just the two mentioned (i.e. distutils and distutils3). Any recipe that inherits distutils* classes are affected. For example, the setuptools and setuptools3 recipes are affected since they inherit the distutils* classes.

Fetching these types of dependencies that are not provided in the sysroot negatively affects the ability to reproduce builds. This type of fetching is now explicitly disabled. Consequently, any missing dependencies in Python recipes that use these classes now result in an error during the do_configure task.

4.14.6 linux-yocto Configuration Audit Issues Now Correctly Reported

Due to a bug, the kernel configuration audit functionality was not writing out any resulting warnings during the build. This issue is now corrected. You might notice these warnings now if you have a custom kernel configuration with a linux-yocto style kernel recipe.

4.14.7 Image/Kernel Artifact Naming Changes

The following changes have been made:

  • Name variables (e.g. IMAGE_NAME) use a new IMAGE_VERSION_SUFFIX variable instead of DATETIME. Using IMAGE_VERSION_SUFFIX allows easier and more direct changes.

    The IMAGE_VERSION_SUFFIX variable is set in the bitbake.conf configuration file as follows:

  • Several variables have changed names for consistency:

    Old Variable Name             New Variable Name
  • The MODULE_IMAGE_BASE_NAME variable has been removed. The module tarball name is now controlled directly with the MODULE_TARBALL_NAME variable.

  • The KERNEL_DTB_NAME and KERNEL_DTB_LINK_NAME variables have been introduced to control kernel Device Tree Binary (DTB) artifact names instead of mangling KERNEL_IMAGE_* variables.

  • The KERNEL_FIT_NAME and KERNEL_FIT_LINK_NAME variables have been introduced to specify the name of flattened image tree (FIT) kernel images similar to other deployed artifacts.

  • The MODULE_TARBALL_NAME and MODULE_TARBALL_LINK_NAME variable values no longer include the “module-” prefix or “.tgz” suffix. These parts are now hardcoded so that the values are consistent with other artifact naming variables.

  • Added the INITRAMFS_LINK_NAME variable so that the symlink can be controlled similarly to other artifact types.

  • INITRAMFS_NAME now uses “${PKGE}-${PKGV}-${PKGR}-${MACHINE}${IMAGE_VERSION_SUFFIX}” instead of “${PV}-${PR}-${MACHINE}-${DATETIME}”, which makes it consistent with other variables.

4.14.8 SERIAL_CONSOLE Deprecated

The SERIAL_CONSOLE variable has been functionally replaced by the SERIAL_CONSOLES variable for some time. With the Yocto Project 2.6 release, SERIAL_CONSOLE has been officially deprecated.

SERIAL_CONSOLE will continue to work as before for the 2.6 release. However, for the sake of future compatibility, it is recommended that you replace all instances of SERIAL_CONSOLE with SERIAL_CONSOLES.


The only difference in usage is that SERIAL_CONSOLES expects entries to be separated using semicolons as compared to SERIAL_CONSOLE, which expects spaces.

4.14.9 Configure Script Reports Unknown Options as Errors

If the configure script reports an unknown option, this now triggers a QA error instead of a warning. Any recipes that previously got away with specifying such unknown options now need to be fixed.

4.14.10 Override Changes

The following changes have occurred:

  • The virtclass-native and virtclass-nativesdk Overrides Have Been Removed: The virtclass-native and virtclass-nativesdk overrides have been deprecated since 2012 in favor of class-native and class-nativesdk, respectively. Both virtclass-native and virtclass-nativesdk are now dropped.


    The virtclass-multilib- overrides for multilib are still valid.

  • The forcevariable Override Now Has a Higher Priority Than libc Overrides: The forcevariable override is documented to be the highest priority override. However, due to a long-standing quirk of how OVERRIDES is set, the libc overrides (e.g. libc-glibc, libc-musl, and so forth) erroneously had a higher priority. This issue is now corrected.

    It is likely this change will not cause any problems. However, it is possible with some unusual configurations that you might see a change in behavior if you were relying on the previous behavior. Be sure to check how you use forcevariable and libc-* overrides in your custom layers and configuration files to ensure they make sense.

  • The build-${BUILD_OS} Override Has Been Removed: The build-${BUILD_OS}, which is typically build-linux, override has been removed because building on a host operating system other than a recent version of Linux is neither supported nor recommended. Dropping the override avoids giving the impression that other host operating systems might be supported.

  • The “_remove” operator now preserves whitespace. Consequently, when specifying list items to remove, be aware that leading and trailing whitespace resulting from the removal is retained.

    See the “Removal (Override Style Syntax)” section in the BitBake User Manual for a detailed example.

4.14.11 systemd Configuration is Now Split Into systemd-conf

The configuration for the systemd recipe has been moved into a system-conf recipe. Moving this configuration to a separate recipe avoids the systemd recipe from becoming machine-specific for cases where machine-specific configurations need to be applied (e.g. for qemu* machines).

Currently, the new recipe packages the following files:


If you previously used bbappend files to append the systemd recipe to change any of the listed files, you must do so for the systemd-conf recipe instead.

4.14.12 Automatic Testing Changes

This section provides information about automatic testing changes:

  • TEST_IMAGE Variable Removed: Prior to this release, you set the TEST_IMAGE variable to “1” to enable automatic testing for successfully built images. The TEST_IMAGE variable no longer exists and has been replaced by the TESTIMAGE_AUTO variable.

  • Inheriting the testimage and testsdk Classes: Best practices now dictate that you use the IMAGE_CLASSES variable rather than the INHERIT variable when you inherit the testimage and testsdk classes used for automatic testing.

4.14.13 OpenSSL Changes

OpenSSL has been upgraded from 1.0 to 1.1. By default, this upgrade could cause problems for recipes that have both versions in their dependency chains. The problem is that both versions cannot be installed together at build time.


It is possible to have both versions of the library at runtime.

4.14.14 BitBake Changes

The server logfile bitbake-cookerdaemon.log is now always placed in the Build Directory instead of the current directory.

4.14.15 Security Changes

The Poky distribution now uses security compiler flags by default. Inclusion of these flags could cause new failures due to stricter checking for various potential security issues in code.

4.14.16 Post Installation Changes

You must explicitly mark post installs to defer to the target. If you want to explicitly defer a postinstall to first boot on the target rather than at rootfs creation time, use pkg_postinst_ontarget() or call postinst_intercept delay_to_first_boot from pkg_postinst(). Any failure of a pkg_postinst() script (including exit 1) triggers an error during the do_rootfs task.

For more information on post-installation behavior, see the “Post-Installation Scripts” section in the Yocto Project Development Tasks Manual.

4.14.17 Python 3 Profile-Guided Optimization

The python3 recipe now enables profile-guided optimization. Using this optimization requires a little extra build time in exchange for improved performance on the target at runtime. Additionally, the optimization is only enabled if the current MACHINE has support for user-mode emulation in QEMU (i.e. “qemu-usermode” is in MACHINE_FEATURES, which it is by default).

If you wish to disable Python profile-guided optimization regardless of the value of MACHINE_FEATURES, then ensure that PACKAGECONFIG for the python3 recipe does not contain “pgo”. You could accomplish the latter using the following at the configuration level:

PACKAGECONFIG_remove_pn-python3 = "pgo"

Alternatively, you can set PACKAGECONFIG using an append file for the python3 recipe.

4.14.18 Miscellaneous Changes

The following miscellaneous changes occurred:

  • Default to using the Thumb-2 instruction set for armv7a and above. If you have any custom recipes that build software that needs to be built with the ARM instruction set, change the recipe to set the instruction set as follows:

  • run-postinsts no longer uses /etc/*-postinsts for dpkg/opkg in favor of built-in postinst support. RPM behavior remains unchanged.

  • The NOISO and NOHDD variables are no longer used. You now control building *.iso and *.hddimg image types directly by using the IMAGE_FSTYPES variable.

  • The scripts/contrib/mkefidisk.sh has been removed in favor of Wic.

  • kernel-modules has been removed from RRECOMMENDS for qemumips and qemumips64 machines. Removal also impacts the x86-base.inc file.


    genericx86 and genericx86-64 retain kernel-modules as part of the RRECOMMENDS variable setting.

  • The LGPLv2_WHITELIST_GPL-3.0 variable has been removed. If you are setting this variable in your configuration, set or append it to the WHITELIST_GPL-3.0 variable instead.

  • ${ASNEEDED} is now included in the TARGET_LDFLAGS variable directly. The remaining definitions from meta/conf/distro/include/as-needed.inc have been moved to corresponding recipes.

  • Support for DSA host keys has been dropped from the OpenSSH recipes. If you are still using DSA keys, you must switch over to a more secure algorithm as recommended by OpenSSH upstream.

  • The dhcp recipe now uses the dhcpd6.conf configuration file in dhcpd6.service for IPv6 DHCP rather than re-using dhcpd.conf, which is now reserved for IPv4.