I think, the problem is actually in the documentation of initramfs-tools:
the examples and explanations in the initramfs-tools man pages forget to state that you have to source "./scripts/functions" for the various functions to work.
Looking into distribution-provided initramfs scripts however reveals a line saying
I think, the problem is actually in the documentation of initramfs-tools:
the examples and explanations in the initramfs-tools man pages forget to state that you have to source "./scripts/ functions" for the various functions to work. provided initramfs scripts however reveals a line saying
Looking into distribution-
. ./scripts/functions
that should make the functions work