support for older firmware revisions (pre-loader)

[jdunn]

In 0.99 there may be a communication problem with older firmware versions (0x0004 specifically) that is causing strange delays. It sounds a lot like the problem when the entire send buffer was being transmitted instead of just the valid portion. This problem occurred between versions 0.95 and 0.99 of the driver.

Comparing the data actually flowing to a 0x0004 device between those two version should allow me to chase down the problem fairly quickly.