Hi Alexander, Building the kernel standalone is not really supported at the moment except for the few configurations where the kernel has been or is intending to be verified. x86-64 is a verification target, and so has a working standalone build, ia32 is not. In particular the standalone build will use a premade autoconf.h file for the platform, for pc99 it is https://github.com/seL4/seL4/blob/master/configs/pc99/autoconf.h, which explicitly declares various x86-64 related configuration settings. If you really want to do standalone ia32 builds the easiest way is to probably just overwrite this file with your own. This currently situation of configuring and building the kernel is undesirable for various reasons (even for us internally that typically build the kernel through our greater project build system). Whilst this doesn't help you right now we have been developing some additions to the build system (both for the kernel and projects) that will fix all this standalone vs project build/configuration frustration. Although they may not land for a month or two. Until then your best options are * Build the kernel (via 'make kernel_elf') from a configured project directory ala sel4test * Build x86-64 * Overwrite the autoconf.h Adrian On Tue 13-Jun-2017 7:31 PM, Alexander Boettcher wrote: On 13.06.2017 11:08, Alexander Boettcher wrote: alex@max:~/sel4.git$mailto:alex@max:~/sel4.git$ ARCH=x86 PLAT=pc99 SEL4_ARCH=ia32 make it seems a ia32 only issue, using x86_64 succeeds. release SEL4_ARCH=ia32/x86_64 ------------------- 3.2.0 - ok/ok 4.0.0 - fails/ok 5.0.0 - fails/ok 5.1.0 - fails/ok 5.2.0 - fails/ok