Hello Joel,<br /><br />thanks for your reply. I was not aware about this possibility. I have tried it and the preemptive rt kernel is built instead of standard ("linux-raspberrypi4_64-preempt-rt-build" is available in build/work/linux-raspberrypi/...) but still the configuration file does not set the CONFIG_PREEMPT_RT=y for raspberrypi4-64, even if a .cfg is added using a .bbappend file. So in the end the RT option is not enabled.<br /><br />Any idea why it works for raspberrypi4 but not for raspberrypi4-64?<br /><br />Best Regards,<br />Carles