Every Boot Loader Interface variable that couldn't be read, written, or
removed aborted boot. The interface only exchanges information with the
operating system, so log a warning and continue instead. This includes
failing to remove LoaderEntryOneShot or LoaderConfigTimeoutOneShot,
which made every following boot fail the same way, as the variable was
never removed.
LoaderConfigTimeoutOneShot asks the boot loader to show the menu on the
next boot, and a value of 0 means the menu waits for the user. Sprout
treated it like LoaderConfigTimeout, so 0 hid the menu, the opposite of
what systemctl reboot --boot-loader-menu=0 asks for, and other values
only changed the timeout without forcing the menu.
Force the menu when the one-shot timeout is set, waiting for the user
when it is 0.
EFI string variables written without a trailing NUL, or with extra NUL
padding, failed to decode and were silently treated as unset. Decode up
to the first NUL and terminate the string ourselves, as systemd-boot
does.
Because empty values now decode to an empty string rather than failing,
treat empty LoaderEntryDefault and LoaderEntryOneShot values as unset so
an empty one-shot entry doesn't fail to match any entry.
A LoaderConfigTimeout or LoaderConfigTimeoutOneShot value that is not a
number or a known keyword made Sprout abort boot. Log a warning and
treat the variable as unset instead, matching systemd-boot.
alex