CONFIG_MODULE_SIG_KEY="certs/signing_key.pem" helped, the kernel was built but it failed then on the RPM building: --- depmod: ERROR: could not open directory /home/db/rpmbuild/BUILDROOT/kernel-6.2.12_1_test-1.x86_64/lib/modules/6.2.12-1-test: No such file or directory depmod: FATAL: could not search modules: No such file or directory make[2]: *** [Makefile:1966: modules_install] Error 1 error: Bad exit status from /var/tmp/rpm-tmp.pOURt0 (%install) RPM build warnings: line 23: It's not recommended to have unversioned Obsoletes: Obsoletes: kernel-headers RPM build errors: Bad exit status from /var/tmp/rpm-tmp.pOURt0 (%install) make[1]: *** [scripts/Makefile.package:81: binrpm-pkg] Error 1 make: *** [Makefile:1680: binrpm-pkg] Error 2 --- depmod looks for modules in lib/modules/6.2.12-1-test but it seems they were installed in usr/lib/modules/6.2.12-1-test: --- INSTALL /home/db/rpmbuild/BUILDROOT/kernel-6.2.12_1_test-1.x86_64/usr/lib/modules/6.2.12-1-test/kernel/net/hsr/hsr.ko INSTALL /home/db/rpmbuild/BUILDROOT/kernel-6.2.12_1_test-1.x86_64/usr/lib/modules/6.2.12-1-test/kernel/net/qrtr/qrtr.ko INSTALL /home/db/rpmbuild/BUILDROOT/kernel-6.2.12_1_test-1.x86_64/usr/lib/modules/6.2.12-1-test/kernel/net/qrtr/qrtr-smd.ko --- I changed MODLIB in Makefile from $(INSTALL_MOD_PATH)/usr/lib/modules/$(KERNELRELEASE) to $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE) and make binrpm-pkg seems to have completed successfully. The source also contains a file named Makefilee that has the "correct" MODLIB value. Is this perhaps some unfinished work since the /usr merge?