I am having this very same issue. If I run udevadm trigger --type=subsystems --action=add udevadm trigger --type=devices --action=add
in the initramdfs shell, it does nothing at all. However, if I run udevadm trigger --type=subsystems --action=add -v udevadm trigger --type=devices --action=add -v it loads the necessary modules. Adding the extra `-v` to the initramfs-tools script seems to work, but makes the boot quite bloated of text :-)
