#!/bin/bash
## 
# Add xhci-pci.ko and ohci-pci.ko into initrd
# Need sys-fs/squashfs-tools, app-arch/xz-utils, app-arch/cpio, app-cdr/cdrtools and sys-boot/syslinux

IMAGE=install-amd64-minimal-20150924

## mount iso image, copy contents do disk and umount it
mount -o loop ${IMAGE}.iso /mnt/cdrom/
mkdir install_img_dir
cp -a /mnt/cdrom/* install_img_dir/
umount /mnt/cdrom/

## extract xhci-pci.ko and ohci-pci.ko from image.squashfs
mkdir workdir
cd workdir
unsquashfs ../install_img_dir/image.squashfs lib64/modules/4.0.5-gentoo/kernel/drivers/usb/host/xhci-pci.ko lib64/modules/4.0.5-gentoo/kernel/drivers/usb/host/ohci-pci.ko

## unpack initrd
xz -d -c < ../install_img_dir/isolinux/gentoo.igz > gentoo
mkdir initrd
cd initrd
cpio -i < ../gentoo

## add missing xhci-pci.ko and ohci-pci.ko to unpacked initrd
cp ../squashfs-root/lib64/modules/4.0.5-gentoo/kernel/drivers/usb/host/?hci-pci.ko lib64/modules/4.0.5-gentoo/kernel/drivers/usb/host/
## and registrate it
sed -ie '1ixhci-pci\nohci-pci' etc/modules/usb

## pack initrd back
find . -print0 | cpio -o -0 -H newc > ../gentoo
cd ..
xz -e --check=none -z -f -9 gentoo

## copy it to contents if iso image
cp gentoo.xz ../install_img_dir/isolinux/gentoo.igz

## make hybrid iso image
cd ..
mkisofs -o ${IMAGE}-Xhci-pci.iso -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -R install_img_dir
isohybrid ${IMAGE}-Xhci-pci.iso