Re: Multiple boot from USB stick

[Karsten Malcher]

Am 14.02.2016 um 07:35 schrieb Andrei Borzenkov:
> grub cannot "boot ISO". What is possible is to access filesystem on ISO and 
> load individual files. If loaded file can
> then access ISO image it is close enough to "boot from ISO image". 

O.K. I understand now. Thanks.

> That probably won't work without extra help. Loaded FreeDOS would need
> access to image as device, and this will require some resident driver to
> emulate access.

Then it is not possible to use the complete ISO image provided.
http://www.freedos.org/download/

I can find the following files in /ISO9660/ISOLINUX

 360K Jan  1  2012 FDBOOT.IMG
 6,7K Aug  6  2011 IFMEMDSK.C32
  24K Dez  9  2011 ISOLINUX.BIN
 2,4K Jan  1  2012 ISOLINUX.CFG
  26K Dez  9  2011 MEMDISK
  55K Dez  9  2011 MENU.C32

I was not able to boot this (see experiments below)

There can be downloaded an image for a floppy that works.
 1,5M Feb 14 11:34 fdboot.img


The iso image for the BIOS updater looks complete different.
There are 3 directories:
  El Torito Boot
  El Torito BootJoliet level 3
  ISO9660

but only "El Torito Boot" is filled with 2 files:
 2,0K Feb 13 11:18 Catalog
 1,5M Feb 13 11:18 Default Image

In my experiments i renamed this "Default Image" to /boot/img/BIOS.img

>
> There were reports that is works using Sylinux memdisk with Smart Boot
> Manager. They can be loaded by GRUB if needed.

That's what i mean - there are no examples how to master it.
I understand what must be done, but it is to complicated in detail.
The documentation does not help to solve such complex problems.

Grub has great features - but nobody knows how to use it !?

> Almost identical question was discussed recently, you could search list
> archive for last couple of weeks for additional information.

Yes - there is a discussion.
But i could not find any concrete solution.

I made some concrete experiments and here are the results:

-------------------------------------------------

menuentry "BIOS update linux16" {
        linux16 /boot/img/BIOS.img
}

error: too many setup sectors.

-------------------------------------------------

menuentry "BIOS update chainloader" {
        set root=(hd0,1)
        chainloader=/boot/img/BIOS.img
}

nothing happens - going back into the boot menu

-------------------------------------------------

menuentry "Flash BIOS memdisk" {
        insmod fat
        set root='(hd0,1)'
        linux16 /boot/img/MEMDISK
        initrd16 /boot/img/BIOS.img
}

MEMDISK 4.05 started
...

Loading boot sector... booting...
Starting...

then it hangs.

-------------------------------------------------

menuentry "FreeDOS Image 1.4MB" {
        insmod fat
        set root='(hd0,msdos1)'
        linux16 /boot/img/MEMDISK
        initrd16 /boot/img/fdboot.img
}

Starting with FreeDOS boot menu
Works with option 2 (Safe Mode without drivers)

Start with option 3 (Live CD with HIMEM + EMM386) but crashes on DIR because 
missing CD

-------------------------------------------------

menuentry "FreeDOS ISO Image Isolinux" {
        set isofile="/boot/iso/FreeDOS_1.1.iso"
        loopback loop (hd0,1)$isofile
        set root='(hd0,msdos1)'
        linux (loop)/ISOLINUX/MEMDISK
        initrd (loop)/ISOLINUX/FDBOOT.IMG

}

Just reboots after a while

-------------------------------------------------

menuentry "Ubuntu 12.04 ISO" {
        set isofile="/boot/iso/kubuntu-12.04.3-desktop-i386.iso"
        loopback loop (hd0,1)$isofile
        linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=$isofile 
noprompt noeject
        initrd (loop)/casper/initrd.lz
}

This is working!
Boots like starting from CD direct into KDE