After increasing the boot image size in local.conf (MENDER_BOOT_PART_SIZE_MB) I got the following error message:
NOTE: Executing Tasks ERROR: mender-client-3.0.0-r0 do_install: Command '['rm', '-rf', '/yocto_project/build/tmp/work/cortexa7t2hf-neon-vfpv4-poky-linux-gnueabi/mender-client/3.0.0-r0/image']' died with <Signals.SIGABRT: 6>. ERROR: Logfile of failure stored in: /yocto_project/build/tmp/work/cortexa7t2hf-neon-vfpv4-poky-linux-gnueabi/mender-client/3.0.0-r0/temp/log.do_install.11677 Log data follows: ... | DEBUG: Python function extend_recipe_sysroot finished | abort()ing pseudo client by server request. See https://wiki.yoctoproject.org/wiki/Pseudo_Abort for more details on this. | Check logfile: /yocto_project/build/tmp/work/cortexa7t2hf-neon-vfpv4-poky-linux-gnueabi/mender-client/3.0.0-r0/pseudo//pseudo.log | ERROR: Command '['rm', '-rf', '/yocto_project/build/tmp/work/cortexa7t2hf-neon-vfpv4-poky-linux-gnueabi/mender-client/3.0.0-r0/image']' died with <Signals.SIGABRT: 6>. ERROR: Task (/yocto_project/sources/meta-mender/meta-mender-core/recipes-mender/mender-client/mender-client_3.0.0.bb:do_install) failed with exit code '1' NOTE: Tasks Summary: Attempted 4477 tasks of which 4471 didn't need to be rerun and 1 failed.
After I deleted the folder manually and restarted the image build process it worked successfully.
According to the linked article, I guess the following happened: “If you see an abort(), it likely means a file was deleted in a non-pseudo context but was left in pseudo’s database.”
If my understanding of the problem is correct then the way Mender handles the changed boot partition size should probably be handled differently to prevent this error.