Re: Trying to use grub on an HD-image

[Christoph Plattner]

Hello !

Interesting experiments you do here, I did similar work some weeks
ago to produce a partition disk image offline.

First of all, you do not need to construct such a image with 64B
fdisk data. Simple use `fdisk /tmp/<IMAGE-FILE>' and setup virtual
geometry data.

But I did not know, whats the problem here. Retry it with the fdisk
method I described above, perhaps it helps because of the consistence
geometry data.

With friendly regards
Christoph P.


"Harmon S. Nine" wrote:
> 
> Hi.  I'm trying to install grub on a hard-drive image that is in my /tmp
> directory in Debian Linux.
> I construct the image by first giving it 64 blocks (of 512 bytes each),
> which are meant to act as the
> MBR and a blank area where e2fs_stage1_5 can be installed.
> 
> In the "MBR", I place a bunch of zeroes in the first 446 bytes, then a
> phony 64B partition table, and then
> the aa55 signature.
> 
> The phony partition table consists of all zeroes, except for the first
> entry.  The first entry states that the first
> "partition" starts at block 64 (i.e. after the 64 blocks described
> above), is of type "linux" (i.e. 0x83), and contains
> however many blocks are needed by the filesystem that the partition will
> contain for this particular hard-drive
> image.  Importantly, since the hard-drive image has no "geometry" to
> speak of, I fill in the
> start and end head-sector-cylinder entries with zeroes.  Thus, the first
> partition-table entry in the
> hard-drive image looks like this (bytes are labeled -- BT = bootable, SH
> = Start Head, etc.):
> 
> BT:00  SH:00  SS:00  SC:00  PT:83  EH:00  ES:00  EC:00  SB:40 00 00 00
>  NB:79 44 00 00
> 
> I then add however many blocks the partition is stated to have (here
> 0x00004479) to the hard-drive image,
> and place a filesystem and the needed files in these blocks (a loopback
> device is used to do this).
> 
> I then run "/sbin/grub", with results shown below.  Up to the "install"
> command, grub is quite happy with the
> image, and e2fs_stage1_5 is embedded at the proper location.
>  Unfortunately, stage1 doesn't
> want to install (I also tried --force-lba).
> 
> What can I do about this?
> 
> TIA
> 
> -- Harmon S. Nine
> 
> -------------------- OUTPUT ----------------
>     GRUB  version 0.90  (640K lower / 3072K upper memory)
> 
>  [ Minimal BASH-like line editing is supported.  For the first word, TAB
>    lists possible command completions.  Anywhere else TAB lists the possible
>    completions of a device/filename. ]
> 
> grub> device (hd0) /tmp/HDIMAGE-ktGUc2
> 
> grub> root (hd0,0)
>  Filesystem type is ext2fs, partition type 0x83
> 
> grub> setup (hd0)
>  Checking if "/boot/grub/stage1" exists... yes
>  Checking if "/boot/grub/stage2" exists... yes
>  Checking if "/boot/grub/e2fs_stage1_5" exists... yes
>  Running "embed /boot/grub/e2fs_stage1_5 (hd0)"...  16 sectors are
> embedded. succeeded
>  Running "install /boot/grub/stage1 d (hd0) (hd0)1+16 p
> (hd0,0)/boot/grub/stage2  /boot/grub/menu.lst"... failed
> 
> Error 22: No such partition
> 
> grub>
> ---------------------END OUTPUT-------------------
> 
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