Try passing a rootdelay option to the kernel to allow the kernels USB probe to complete before it tries to mount the USB device.
e.g. kernel /boot/kernel root=/dev/usbhdd rootdelay=30 in grub
Try passing a rootdelay option to the kernel to allow the kernels USB probe to complete before it tries to mount the USB device.
e.g. kernel /boot/kernel root=/dev/usbhdd rootdelay=30 in grub