Bug#534887: live-initramfs: Loop mounting .iso for booting from multi-purpose USB stick?
Philip Hands a écrit :
I also have a versatile USB stick with 10 live-OSes to choose from at
boot-time. But I don't use the .iso loopback support, even when it is
I've been trying to build a versatile USB stick, with the imntent that
it be able to choose between various images at a grub prompt.
For instance it is possible to use Grub2 which has loopback support with
all the many live-OSes which have .iso loopback support. But there is
one layer that will never have loopback support, it is the stage1
bootloader. This result in an inconfortable situation:
-1- A direct jump from grub2 to Linux kernel bypassing all the choices
offered by the genuine stage2 bootloader of the liveCD you have chosen
-2- A huge Grub2 grub.cfg where you have to manually copy all menus
entries from all live OSes
I prefer this way: all liveOSes on the same ext2 partition, each one
with their own filesystems *and* bootloader. I just add a *first*
bootloader which is Extlinux with a very simple menu: one line per
LiveOS to choose from. Choosing a line from this menu, doesn't trigger
the loading of a LiveOS but the loading of the *bootloader* of the
LiveCD, which gives the user the same splash screen and menu choices as
if he had really boot from the physical CD.
Having the choice of many bootloaders on the same partition is very
easy: install each bootloader as usual, (extlinux uses the same config
files as isolinux, just do "ln -s isolinux.cfg extlinux.conf"), but
after each install copy the partition boot sector in a file. To jump
from one bootloader A to bootloader B just ask bootloader A to load the
partition bootsector you have saved when you installed bootloader B. It
is that simple. It works very well for jumping from EXTLINUX to EXTLINUX
or GRUB, but jumping from GRUB to another bootloader is not always that
easy. I found that the only reliable way is asking GRUB to load the
physical boot sector.
This way the user can navigate between as many booloaders he wants (
going back to the first bootloader w/o power on/off is possible by
typing 'x' at the boot prompt because I saved the first bootloader boot
sector as file 'x.bs' and copied it in each isolinux directory)
This is so simple that I have fully automated the process with a
handfull of shell functions.