How to boot an iso from USB drive

Requirements

• USB drive
• Grub4dos
• dd
• fdisk (or something else that does partitions)

Sequence

• Download and extract grub4dos, cd to its directory.
• Plug in your flash drive. Remember its device (I'll use /dev/sde)
• Copy grub4dos MBR to flash drive:

# dd if=grldr.mbr of=/dev/sde
18+0 records in
18+0 records out
9216 bytes (9.2 kB) copied, 0.011999 s, 768 kB/s

• Create new FAT32 partition on your USB drive:
  • Launch fdisk: # fdisk /dev/sde
  • Create new partition on full disk: n, Enter, p, Enter, Enter
  • Press w to write changes and exit fdisk
  • Run mkfs.vfat -F 32 /dev/sde1
• Mount your partition and copy .iso to it:

# mkdir -p /media/sde1
# mount /dev/sde1 /media/sde1
# cp ~/isoz/debian-504-i386-netinst.iso /media/sde1/

• Copy grub4dos binary over:

# cp grldr /media/sde1/

• Edit menu.lst:

# editor /media/sde1/menu.lst

• Add following content to it:

title My cool ISO image
find --set-root /debian-504-i386-netinst.iso
map /debian-504-i386-netinst.iso (0xff)
map --hook
chainloader (0xff)

• Unmount partition:

1. umount /dev/sde1
2. rm -r /media/sde1

If you are lucky, this will boot. If you unlucky (and it says something about uncontinuous), during copying the .iso image it got fragmented. Re-copy and 1. Pray 2. Try to copy .iso on clean disk.

Thanks:

http://grub4dos.sourceforge.net/wiki/index.php/Grub4dos_tutorial

And few more links that I can't remember from http://www.google.com/search?q=grub+boot+iso

And thanks to GRUB2 guys for fucking up config!