The `device.map` configuration file generated by `Anaconda` is sometimes incorrect
Due to limitations in the kernel, the `device.map` configuration file that is used to map BIOS drives to operating system devices might be generated incorrectly in certain situations, particularly when installing from a USB key. As a consequence, booting sometimes fails after installation. To work around this problem, manually update the `device.map` file in the `/boot/grub` directory. After updating `device.map` so that it correctly maps devices on the system, Red Hat Enterprise Linux 6 will boot as expected.