Re: backing up kernel and initramfs for future rescue use with upslug2

[Daniel Kahn Gillmor <dkg-debian.org@fifthhorseman.net>]

Hi Gordon--

On November 25, gordonfarquharson@gmail.com said:

> I have tested this version of the kernel, and it works, so switching
> to it shouldn't be a problem. I wouldn't switch the rest of the
> system to packages from unstable just yet - for instance, there
> appears to be a problem with the version of nslu2-utils in unstable
> that can make the system unbootable.

yikes!  Are you sure?  Has this been reported as a bug yet?

  http://bugs.debian.org/cgi-bin/pkgreport.cgi?which=pkg&data=nslu2-utils&archive=no

> >     Can i just do something like this:
> >
> >      [root@igor]# cat /dev/mtdblock{0,1,2,3,4,5} >/var/backups/flashimage.bak
> >      [root@igor]# scp /var/backups/flashimage.bak backuphost:igor-backups/
> >
> >     and then flash it with upslug2 from backuphost if something goes
> >     wrong?  That does seem to add up to the right bytecount...
> 
> This method works (I do it all the time).

Thanks!  That's really good to know.  And you've tested reflashing
those generated images with upslug2?  That's the bit i'm scared to try
myself on my only functional nslu2.

> A slightly shorter backup command is
> 
> $ cat /dev/mtdblock* > /var/backups/flashimage.bak

Ah, but then you're relying on the shell to expand that glob in
alphabetical order, and i'm always paranoid about things like that...
/reads bash manpage:

   Pathname Expansion
       After  word  splitting,  unless  the -f option has been set, bash scans
       each word for the characters *, ?, and [.  If one of  these  characters
       appears,  then  the word is regarded as a pattern, and replaced with an
       alphabetically sorted list of file names matching the pattern.

Sweet.  i never knew i could trust bash to expand in alphabetical
order (though it's a reasonable choice).  Lots of new information for
me today!

Thanks again,

	--dkg