Since &debian; Squeeze, support for booting in ESA/390 mode was dropped. Your machine needs to support for at least the z/Architecture, Architecture Level Set 2. The userland is still compiled for ESA/390, though. All zSeries hardware is fully supported. &arch-title; support software is included from the kernel 2.6.32 development stream. The most current information about IBM's Linux support can be found at the Linux on System z page on developerWorks.