If you apply the attached patch and run update-initramfs -u -k all that should copy the depmod to your initrds.
--- libsplashy.orig 2011-03-21 00:17:07.000000000 -0300 +++ libsplashy 2011-03-21 00:17:19.000000000 -0300 @@ -51,3 +51,4 @@ mkdir -p $DESTDIR$(dirname $I) copy_exec $I .`dirname $I` done +copy_exec /sbin/depmod /sbin
