GRUB settings of booting from usb disk with genkernel on Gentoo

I’ve tried to use genkernel to build my gentoo box recent days. But I cannot boot correctly via an installation with external USB disk (My gentoo box is on an external USB 2.5″ disk).

The default GRUB settings for genkernel user is:

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title Gentoo Linux 2.6.34-r1
root (hd0,0)
kernel /boot/kernel-genkernel-x86-2.6.34-gentoo-r1 real_root=/dev/sda3
initrd /boot/initramfs-genkernel-x86-2.6.34-gentoo-r1

But with this configuration, the boot procedure will stop at there is not correct root sector can be loaded. That’s because the usb is slower o be configured than my laptop’s disks. And on the other hand, the waitroot, doslowusb, and so on additional configurations cannot be passed to a genkernal-ed source.

For some tries and referenced configurations on other linux distribution, the works setting is to use UUID (UUID=….) rather than aliased device name (dev/$ROOT). The correct settings:

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title Gentoo Linux 2.6.34-r1
root (hd0,0)
kernel /boot/kernel-genkernel-x86-2.6.34-gentoo-r1 real_root=UUID=....
initrd /boot/initramfs-genkernel-x86-2.6.34-gentoo-r1

The UUID for devices can be found in your /etc/fstab if you also use genkernel. Finally, my USB gentoo works fine. Enjoy it. 🙂