Bug#694722: eMachines eM355, encrypted & boots off pendrive, preseeding fails
Hello Brian,
thanks for responding.
On 2012-Nov-30 18:54 (+0000), Brian Potkin wrote with possible deletions:
[gunzip <boot.img.gz >/dev/sdb => failed]
> This works for me.
[gunzip <boot.img.gz >/dev/sdb1 => GRUB error]
> This would not work because the MBR is not written to. There is nothing
> in it to say how to boot.
> I think you may have your comments on the two techniques the wrong way
> round. Also, it is SYSLINUX which does the booting, not GRUB. Did you
> really get a screen with "GRUB" displayed at the top?
Ok, I'm retrying this right now:
# gunzip <boot.img.gz >/dev/sdb
# mount /dev/sdb /media/sdb
# cp debian-wheezy-DI-b4-amd64-netinst.iso /media/sdb
# umount /media/sdb
When I plug the pendrive into the target machine, it hangs. No
boot-menu, just a blinking cursor. Now let me retry the other version:
# dd if=/dev/zero of=/dev/sdb
# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x1b9f17d2.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
Command (m for help): p
Disk /dev/sdb: 4025 MB, 4025810432 bytes
124 heads, 62 sectors/track, 1022 cylinders, total 7862911 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x1b9f17d2
Device Boot Start End Blocks Id System
Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): p
Partition number (1-4, default 1):
Using default value 1
First sector (2048-7862910, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-7862910, default 7862910):
Using default value 7862910
Command (m for help): p
Disk /dev/sdb: 4025 MB, 4025810432 bytes
124 heads, 62 sectors/track, 1022 cylinders, total 7862911 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x1b9f17d2
Device Boot Start End Blocks Id System
/dev/sdb1 2048 7862910 3930431+ 83 Linux
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
# gunzip <boot.img.gz >/dev/sdb1
# mount /dev/sdb1 /media/sdb1
# cp debian-wheezy-DI-b4-amd64-netinst.iso /media/sdb1
# umount /media/sdb1
Ok, pendrive goes to target machine again. Nothing happens this time,
just a blinking cursor in the top left corner, just as above. No boot
menu, no GRUB. So you were right:
> This would not work because the MBR is not written to. There is nothing
> in it to say how to boot.
It is hard for me now to figure out what happened last time, when I've
seen the GRUB error message. I'm sure it was GRUB, because I ended up
in it's rescue mode. Would it be possible that a GRUB survived
somewhere else on the target machine's harddisk from a previous install,
and the BIOS fell back to launch that one, since nothing was found on
the pendrive's MBR? Anyways, since I cannot reproduce it, it's not a
bug.
So I try the preseeding as you told me, using a new partition on the
pendrive I've set up with
# dd if=debian-wheezy-DI-b4-amd64-netinst.iso of=/dev/sdb
Pretty awesome! The installer seems to ignore the ESSID I've set
for wifi, but that's the only issue I can put my finger on. I'm pretty
happy.
Is there a definitive documentation of the syntax, semantics, and
possible values I can put in my `preseed.cfg`?
Thank you!
Stefan
--
Stefan Klinger o/klettern
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