TIP Boot Floppydisk Image without Floppy using GRUB

From Gentoo Linux Wiki

Maybe you know the trouble of getting either a floppy disk or even a diskdrive ready, when you have to flash some hardware in your PC. But with little effort you can use grub to boot a floppy disk image from the harddisk.

I assume grub is installed correctly.

[edit] Preparations

We'll need memdisk from sys-boot/syslinux. Last time I checked syslinux depended on sys-fs/mtools, which will be very useful for us, too. (So if it does not fetch mtools automatically emerge them, too) emerge syslinux.

Now we'll create a new directory (I called it dos, use whatever you feel comfortable with) as we don't want to clutter /boot and copy the memdisk utility there:

If you placed /boot on a separate partition mount it first!

mount /boot
mkdir /boot/dos
cp /usr/lib/syslinux/memdisk /boot/dos/

[edit] Getting a disk image

Now we'll have to get the disk image we want to boot into this directory. If you don't know where to get one check this HOWTO or [1].

cp /path/to/your/imagefile.img /boot/dos/

[edit] Configuring mtools

As we might want to edit the disk before booting (e.g. to copy a bios flasher + bios onto it), we have to configure mtools:

cp /etc/mtools/mtools.conf.example /etc/mtools/mtools.conf

Follow the comments in this file and setup a line like drive b: file="/boot/dos/imagefile.img"

Now you can use mdir b: to list the contents of the image. To copy files to the image you can use mcopy, to delete files use mdel, etc.

[edit] Editing grub.conf

Now we'll have to tell grub about this new bootoption, so edit /boot/grub/grub.conf to include this:

...
/boot/grub/grub.conf:
title DosFlashDisk
kernel /dos/memdisk
initrd /dos/imagefile.img
...

You may want to password-protect that entry, as it can be dangerous if someone untrusted and skilled can boot up a less secure OS on your computer.

[edit] Testing

When you're done unmount /boot and restart to see, if the new entry in grub works.

Happy flashing.