Short read of zdata file

James Cameron quozl at
Thu Feb 23 18:57:22 EST 2012

On XO-1.5 and XO-1.75, during fs-update, an error may occur "Short read
of zdata file".

If this occurs, the fs-update has been aborted, and the installation of
the operating system is incomplete.  The laptop is unlikely to work well
in this condition.

The causes vary:

1.  the file download from the internet may have been interrupted ...
easy to recognise because the file size won't match what it should, and
easy to fix by resuming [1] or repeating the download,

2.  the file copy to the USB drive may have been interrupted, e.g. by
lack of space,

3.  the USB drive FAT32 filesystem may have a high nibble set in the
cluster chain, causing an incompatibility, which will be fixed [2] in
the next version of OpenFirmware, ... (in my testing the affected USB
drives were used on Mac OS X, but the symptom does not repeat).

4.  something went wrong with the USB drive itself, ... may be avoided
by using a different USB drive,

5.  the USB drive was removed from the laptop, or the contacts were
briefly open due to a mechanical fault, ... try a different port and a
different USB drive,

6.  something went wrong with the preparation of the filesystem image,
... but this would affect all users,




James Cameron

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