4.10 Moving to the Yocto Project 2.2 Release

This section provides migration information for moving to the Yocto Project 2.2 Release from the prior release.

4.10.1 Minimum Kernel Version

The minimum kernel version for the target system and for SDK is now 3.2.0, due to the upgrade to glibc 2.24. Specifically, for AArch64-based targets the version is 3.14. For Nios II-based targets, the minimum kernel version is 3.19.


For x86 and x86_64, you can reset OLDEST_KERNEL to anything down to 2.6.32 if desired.

4.10.2 Staging Directories in Sysroot Has Been Simplified

The way directories are staged in sysroot has been simplified and introduces the new SYSROOT_DIRS, SYSROOT_DIRS_NATIVE, and SYSROOT_DIRS_BLACKLIST. See the v2 patch series on the OE-Core Mailing List for additional information.

4.10.3 Removal of Old Images and Other Files in tmp/deploy Now Enabled

Removal of old images and other files in tmp/deploy/ is now enabled by default due to a new staging method used for those files. As a result of this change, the RM_OLD_IMAGE variable is now redundant.

4.10.4 Python Changes

The following changes for Python occurred: BitBake Now Requires Python 3.4+

BitBake requires Python 3.4 or greater. UTF-8 Locale Required on Build Host

A UTF-8 locale is required on the build host due to Python 3. Since C.UTF-8 is not a standard, the default is en_US.UTF-8. Metadata Must Now Use Python 3 Syntax

The metadata is now required to use Python 3 syntax. For help preparing metadata, see any of the many Python 3 porting guides available. Alternatively, you can reference the conversion commits for Bitbake and you can use OpenEmbedded-Core (OE-Core) as a guide for changes. Following are particular areas of interest:

  • subprocess command-line pipes needing locale decoding

  • the syntax for octal values changed

  • the iter*() functions changed name

  • iterators now return views, not lists

  • changed names for Python modules Target Python Recipes Switched to Python 3

Most target Python recipes have now been switched to Python 3. Unfortunately, systems using RPM as a package manager and providing online package-manager support through SMART still require Python 2.


Python 2 and recipes that use it can still be built for the target as with previous versions. buildtools-tarball Includes Python 3

buildtools-tarball now includes Python 3.

4.10.5 uClibc Replaced by musl

uClibc has been removed in favor of musl. Musl has matured, is better maintained, and is compatible with a wider range of applications as compared to uClibc.

4.10.6 ${B} No Longer Default Working Directory for Tasks

${B} is no longer the default working directory for tasks. Consequently, any custom tasks you define now need to either have the [dirs] flag set, or the task needs to change into the appropriate working directory manually (e.g using cd for a shell task).


The preferred method is to use the [dirs] flag.

4.10.7 runqemu Ported to Python

runqemu has been ported to Python and has changed behavior in some cases. Previous usage patterns continue to be supported.

The new runqemu is a Python script. Machine knowledge is no longer hardcoded into runqemu. You can choose to use the qemuboot configuration file to define the BSP’s own arguments and to make it bootable with runqemu. If you use a configuration file, use the following form:


The configuration file enables fine-grained tuning of options passed to QEMU without the runqemu script hard-coding any knowledge about different machines. Using a configuration file is particularly convenient when trying to use QEMU with machines other than the qemu* machines in OpenEmbedded-Core (OE-Core). The qemuboot.conf file is generated by the qemuboot class when the root filesystem is being build (i.e. build rootfs). QEMU boot arguments can be set in BSP’s configuration file and the qemuboot class will save them to qemuboot.conf.

If you want to use runqemu without a configuration file, use the following command form:

$ runqemu machine rootfs kernel [options]

Supported machines are as follows:

  • qemuarm

  • qemuarm64

  • qemux86

  • qemux86-64

  • qemuppc

  • qemumips

  • qemumips64

  • qemumipsel

  • qemumips64el

Consider the following example, which uses the qemux86-64 machine, provides a root filesystem, provides an image, and uses the nographic option:

$ runqemu qemux86-64 tmp/deploy/images/qemux86-64/core-image-minimal-qemux86-64.ext4 tmp/deploy/images/qemux86-64/bzImage nographic

Following is a list of variables that can be set in configuration files such as bsp.conf to enable the BSP to be booted by runqemu:


“QB” means “QEMU Boot”.

QB_SYSTEM_NAME: QEMU name (e.g. "qemu-system-i386")
QB_OPT_APPEND: Options to append to QEMU (e.g. "-show-cursor")
QB_DEFAULT_KERNEL: Default kernel to boot (e.g. "bzImage")
QB_DEFAULT_FSTYPE: Default FSTYPE to boot (e.g. "ext4")
QB_MEM: Memory (e.g. "-m 512")
QB_MACHINE: QEMU machine (e.g. "-machine virt")
QB_CPU: QEMU cpu (e.g. "-cpu qemu32")
QB_CPU_KVM: Similar to QB_CPU except used for kvm support (e.g. "-cpu kvm64")
QB_KERNEL_CMDLINE_APPEND: Options to append to the kernel's -append
                          option (e.g. "console=ttyS0 console=tty")
QB_DTB: QEMU dtb name
QB_AUDIO_DRV: QEMU audio driver (e.g. "alsa", set it when support audio)
QB_AUDIO_OPT: QEMU audio option (e.g. "-soundhw ac97,es1370"), which is used
              when QB_AUDIO_DRV is set.
QB_KERNEL_ROOT: Kernel's root (e.g. /dev/vda)
QB_TAP_OPT: Network option for 'tap' mode (e.g.
            "-netdev tap,id=net0,ifname=@TAP@,script=no,downscript=no -device virtio-net-device,netdev=net0").
             runqemu will replace "@TAP@" with the one that is used, such as tap0, tap1 ...
QB_SLIRP_OPT: Network option for SLIRP mode (e.g. "-netdev user,id=net0 -device virtio-net-device,netdev=net0")
QB_ROOTFS_OPT: Used as rootfs (e.g.
               "-drive id=disk0,file=@ROOTFS@,if=none,format=raw -device virtio-blk-device,drive=disk0").
               runqemu will replace "@ROOTFS@" with the one which is used, such as
QB_SERIAL_OPT: Serial port (e.g. "-serial mon:stdio")
QB_TCPSERIAL_OPT: tcp serial port option (e.g.
                  " -device virtio-serial-device -chardev socket,id=virtcon,port=@PORT@,host= -device      virtconsole,chardev=virtcon"
                  runqemu will replace "@PORT@" with the port number which is used.

To use runqemu, set IMAGE_CLASSES as follows and run runqemu:


For command-line syntax, use runqemu help.

IMAGE_CLASSES += "qemuboot"

4.10.8 Default Linker Hash Style Changed

The default linker hash style for gcc-cross is now “sysv” in order to catch recipes that are building software without using the OpenEmbedded LDFLAGS. This change could result in seeing some “No GNU_HASH in the elf binary” QA issues when building such recipes. You need to fix these recipes so that they use the expected LDFLAGS. Depending on how the software is built, the build system used by the software (e.g. a Makefile) might need to be patched. However, sometimes making this fix is as simple as adding the following to the recipe:



The KERNEL_IMAGE_BASE_NAME variable no longer uses the KERNEL_IMAGETYPE variable to create the image’s base name. Because the OpenEmbedded build system can now build multiple kernel image types, this part of the kernel image base name as been removed leaving only the following:


If you have recipes or classes that use KERNEL_IMAGE_BASE_NAME directly, you might need to update the references to ensure they continue to work.

4.10.10 BitBake Changes

The following changes took place for BitBake:

  • The “goggle” UI and standalone image-writer tool have been removed as they both require GTK+ 2.0 and were not being maintained.

  • The Perforce fetcher now supports SRCREV for specifying the source revision to use, be it ${AUTOREV}, changelist number, p4date, or label, in preference to separate SRC_URI parameters to specify these. This change is more in-line with how the other fetchers work for source control systems. Recipes that fetch from Perforce will need to be updated to use SRCREV in place of specifying the source revision within SRC_URI.

  • Some of BitBake’s internal code structures for accessing the recipe cache needed to be changed to support the new multi-configuration functionality. These changes will affect external tools that use BitBake’s tinfoil module. For information on these changes, see the changes made to the scripts supplied with OpenEmbedded-Core: 1 and 2.

  • The task management code has been rewritten to avoid using ID indirection in order to improve performance. This change is unlikely to cause any problems for most users. However, the setscene verification function as pointed to by BB_SETSCENE_VERIFY_FUNCTION needed to change signature. Consequently, a new variable named BB_SETSCENE_VERIFY_FUNCTION2 has been added allowing multiple versions of BitBake to work with suitably written metadata, which includes OpenEmbedded-Core and Poky. Anyone with custom BitBake task scheduler code might also need to update the code to handle the new structure.

4.10.11 Swabber has Been Removed

Swabber, a tool that was intended to detect host contamination in the build process, has been removed, as it has been unmaintained and unused for some time and was never particularly effective. The OpenEmbedded build system has since incorporated a number of mechanisms including enhanced QA checks that mean that there is less of a need for such a tool.

4.10.12 Removed Recipes

The following recipes have been removed:

  • augeas: No longer needed and has been moved to meta-oe.

  • directfb: Unmaintained and has been moved to meta-oe.

  • gcc: Removed 4.9 version. Versions 5.4 and 6.2 are still present.

  • gnome-doc-utils: No longer needed.

  • gtk-doc-stub: Replaced by gtk-doc.

  • gtk-engines: No longer needed and has been moved to meta-gnome.

  • gtk-sato-engine: Became obsolete.

  • libglade: No longer needed and has been moved to meta-oe.

  • libmad: Unmaintained and functionally replaced by libmpg123. libmad has been moved to meta-oe.

  • libowl: Became obsolete.

  • libxsettings-client: No longer needed.

  • oh-puzzles: Functionally replaced by puzzles.

  • oprofileui: Became obsolete. OProfile has been largely supplanted by perf.

  • packagegroup-core-directfb.bb: Removed.

  • core-image-directfb.bb: Removed.

  • pointercal: No longer needed and has been moved to meta-oe.

  • python-imaging: No longer needed and moved to meta-python

  • python-pyrex: No longer needed and moved to meta-python.

  • sato-icon-theme: Became obsolete.

  • swabber-native: Swabber has been removed. See the entry on Swabber.

  • tslib: No longer needed and has been moved to meta-oe.

  • uclibc: Removed in favor of musl.

  • xtscal: No longer needed and moved to meta-oe

4.10.13 Removed Classes

The following classes have been removed:

  • distutils-native-base: No longer needed.

  • distutils3-native-base: No longer needed.

  • sdl: Only set DEPENDS and SECTION, which are better set within the recipe instead.

  • sip: Mostly unused.

  • swabber: See the entry on Swabber.

4.10.14 Minor Packaging Changes

The following minor packaging changes have occurred:

  • grub: Split grub-editenv into its own package.

  • systemd: Split container and vm related units into a new package, systemd-container.

  • util-linux: Moved prlimit to a separate util-linux-prlimit package.

4.10.15 Miscellaneous Changes

The following miscellaneous changes have occurred:

  • package_regex.inc: Removed because the definitions package_regex.inc previously contained have been moved to their respective recipes.

  • Both devtool add and recipetool create now use a fixed SRCREV by default when fetching from a Git repository. You can override this in either case to use ${AUTOREV} instead by using the -a or DASHDASHautorev command-line option

  • distcc: GTK+ UI is now disabled by default.

  • packagegroup-core-tools-testapps: Removed Piglit.

  • image.bbclass: Renamed COMPRESS(ION) to CONVERSION. This change means that COMPRESSIONTYPES, COMPRESS_DEPENDS and COMPRESS_CMD are deprecated in favor of CONVERSIONTYPES, CONVERSION_DEPENDS and CONVERSION_CMD. The COMPRESS* variable names will still work in the 2.2 release but metadata that does not need to be backwards-compatible should be changed to use the new names as the COMPRESS* ones will be removed in a future release.

  • gtk-doc: A full version of gtk-doc is now made available. However, some old software might not be capable of using the current version of gtk-doc to build documentation. You need to change recipes that build such software so that they explicitly disable building documentation with gtk-doc.