When building an initrd image, it is common to preload modules by simple names like scsi_mod. how does initrd convert that alias, scsi_mod, into an absolute system path, i.e. /lib/modules/<kernel-name>/kernel/drivers/scsi/mod_scsi.ko that it can then load?
if the alias is taken from the build environment, then initrd gets the wrong path, i.e. the path to the CURRENT scsi_mod.ko module.