As already mentioned before, there is unfortunately no standard for system firmware on ARM systems. Even the behaviour of different systems which use nominally the same firmware can be quite different. This results from the fact that a large part of the devices using the ARM architecture are embedded systems, for which the manufacturers usually build heavily customized firmware versions and include device-specific patches. Unfortunately the manufacturers often do not submit their changes and extensions back to the mainline firmware developers, so their changes are not integrated into newer versions of the original firmware. As a result even newly sold systems often use a firmware that is based on a years-old manufacturer-modified version of a firmware whose mainline codebase has evolved a lot further in the meantime and offers additional features or shows different behaviour in certain aspects. In addition to that, the naming of onboard devices is not consistent between different manufacturer-modified versions of the same firmware, therefore it is nearly impossible to provide usable product-independend instructions for ARM-based systems.