Re: can't boot a Debian on QEMU-mips virtual machine, could be initrd or root device problems

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

Reco wrote:
> $ qemu-system-mips -m 2048 -nographic
> -cdrom /tmp/debian-7.4.0-mips-netinst.iso -boot d
> qemu-system-mips: Could not load MIPS bios 'mips_bios.bin', and no -kernel
> argument was specified

Oops. I did not expect it to die so early.


> Also, that 'iso' is no way a conventional ISO9660 or UDF image:
> $ file -sL /tmp/debian-7.4.0-mips-netinst.iso
> /tmp/debian-7.4.0-mips-netinst.iso: SGI disk label (volume header)

Oh, it is. But it is also a bit more than that.
It's only that the programmers of "file" did not account for that
combination as much as they did with x86 isohybrids:

  $ file debian-9.3.0-amd64-netinst.iso
  debian-9.3.0-amd64-netinst.iso: DOS/MBR boot sector ISO 9660 CD-ROM
  filesystem data 'Debian 9.3.0 amd64 n' (bootable); partition 2 : ID=0xef,
  start-CHS (0x3ff,254,63), end-CHS (0x3ff,254,63), startsector 3760,
  832 sectors

With the mips ISO, we have to combine file's report with info like this

  $ isoinfo -i debian-7.4.0-mips-netinst.iso -d
  CD-ROM is in ISO 9660 format
  System id: 
  Volume id: Debian 7.4.0 mips 1
  Volume set id: 
  Publisher id: 
  Data preparer id: XORRISO-1.2.6 2013.01.08.103001, LIBISOBURN-1.2.6, LIBISOFS-1.2.6, LIBBURN-1.2.6
  Application id: 
  Copyright File id: 
  Abstract File id: 
  Bibliographic File id: 
  Volume set size is: 1
  Volume set sequence number is: 1
  Logical block size is: 2048
  Volume size is: 105591
  Joliet with UCS level 3 found
  Rock Ridge signatures version 1 found

xorriso can tell about the MIPS Volume Header which it created on demand
of debian-cd:

  $ xorriso -report_about warning -indev debian-7.4.0-mips-netinst.iso \
            -report_system_area plain 
  System area options: 0x00000004
  System area summary: MIPS-Big-Endian
  ISO image size/512 : 422364
  MIPS-BE volume dir :   N      Name       Block       Bytes
  MIPS-BE boot entry :   1  r4k-ip22       63436    10876928
  MIPS-BE boot path  :   1  /install/r4k-ip22-boot.img

But i guess it will be hard to determine which machines react on this.
My cheat sheet for boot sectors says

                               MIPS Volume Header
                       for MIPS Big Endian, e.g. SGI Indigo2

  Sources:
     cdrkit-1.1.10/genisoimage/boot-mips.c
     by Steve McIntyre <steve@einval.com>
     which refers to
        genisovh by Florian Lohoff <flo@rfc822.org>
                and Thiemo Seufer <seufer@csv.ica.uni-stuttgart.de>
        who seem to have learned parameter settings from IRIX CD media
        There are traces in the web which relate this to specs by
                 MIPS Computer Systems, Inc. , 1985
                 Silicon Graphics Computer Systems, Inc. , 2000
     Mail conversations with Natalia Portillo.


Have a nice day :)

Thomas