Weird behaviour

[James Cameron]

I agree, it seems likely to be a hardware problem with USB.

You said file copy from USB to the filesystem was just as slow.  Is that
using OpenFirmware or Linux?  I'm expecting you used Linux.

We made some USB changes in OpenFirmware, but these ought not to have
had this effect, and should have no effect at all on Linux.  Yet, I am
interested to know what version of OpenFirmware is on the units.

--

For your interest, next time you need it, there's an OpenFirmware test
feature for checking the fs-update transfer rates from USB.

ok null-fsdisk fs-update u:\fs.zd

What it does is read the data from USB and then discard it.  That way
you can exclude the time otherwise spent writing to the internal microSD
or eMMC.  The feature was recently fixed (10th Feb 2012) so use firmware
after that date.  I didn't go back to find when it broke.

-- 
James Cameron
http://quozl.linux.org.au/