Further notes by Tong Sun:

#######################################################################
> I found that the bootfrom=xxx.iso cheatcode does not work as expected.
>
> I notice the following grub boot menu,
>
> title           GRML 0.9 from .ISO on sda2
>   root          (hd0,2)
>   kernel  /boot.grml/isolinux/linux26 welcome noeject noprompt
> ramdisk_size=100000 init=/etc/init lang=us apm=power-off vga=791 nomce
> bootfrom=/dev/sda2/Grml/grml_0.9.iso
>   initrd  /boot.grml/isolinux/minirt26.gz
>   savedefault
>   boot
>
> only works as long as my USB key was plugged in. If not, it won't work.

Using the equvalient syslinux.cfg entry, I was able to boot grml iso from HD
using grml-small from USB, but there is a problem,

> Having Looked into the issue, I realized that,
>
> grml search for grml image in all patitions first before doing the bootfrom=
> cheatcode. When my USB key is plugged in, it can continue on, mounting the
> .iso
> as root the second time, though it report missing /lib/.../modeprobe.dep
> beforehand.

The problem may related to this (unable to load modules). Thy symptom is that
the ifconfig -a only shows lo device, not eth0. If I specified 'ifup eth0', the
respond was no such device or similar. Duplicated the result each time when
tested.

Booting grml-small or grml directly won't have such problem. eth0 works fine.

Test environment: grml 0.9/grml-small 0.3
#######################################################################