The bootloader provides too little information on the LCD

[hnez]

The barebox bootloaders displays the following pieces of information on the screen:

• It tries to boot into root-a …
• … but it failed.
• It tries to boot into root-b …
• … but it failed.

This is not that much information. It would be great to print at least the following additional pieces of information:

• None of the two boot slots have remaining attempts, so none will be booted.
• The boot was interrupted via the console / other manual interruption.

[a3f]

There is a progress notifier feature in <progress.h>. It's not used much at the moment, but it was meant for exactly this:

• Generic code calls progress_notifier_call_chain(PROGRESS_BOOT_FALLBACK, "a message");
• Board code registers a handler with progress_register_client which prints this to the display
• Users not initerested in this functionality just disable CONFIG_PROGRESS_NOTIFIER and incur no extra cost.