What is stage-1?
This is what is also referred as
stage-1 refers to
the fact that this is the first part of the system that gets run once the kernel
has been started.
About "sad phone" screens
It may happen that you have a "sad phone" screen when booting.
This means that a fatal error has happened.
When there is no screen logging available for the device, the general case of error has been codified as a background color.
0xFFFF00) means that mounting the root filesystem was not possible.
0xFF00FF) means that mounting succeeded, but no compatible generation was found to boot.
0xFF0000) means that executing (
exec) and switching to the found generation’s init failed.
0x95681C) means an uncontrolled abort happened.
It may happen that the boot seemingly or actually hangs before a "sad phone" screen appears. In those instances, it means something else earlier kept the early init scripts to continue. In the future, better logging and status reporting will be added to keep track of early failures.