The very first command after init command should be "read target voltage".
This is a tweak for the Old Versaloon firmware. Without this, in most
most cases, it works. Under Ubuntu9.04, there is a chance that the USB
will fail. The problem disappears if I read target voltage first.
For the lastest Versaloon firmware, it's OK.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>