Trouble uploading sketch to redboard on Chbk using stk500

I am developing this online block-based arduino programming tool:

http://www.genlrn.com/iForge

It uses a codebender server to compile the sketch, and it uses a plugin to upload the compiled code to the board.

The plugin is based on the browserDude project, which is a webified version of stk500 node library.

It is important that this works with the Sparkfun redboard.

And it does as long as I’m working on a mac or a pc.

However, when I try to use the program on a chromebook, I now get timeout errors when I try to upload the code. The plugin is able to successfully find the serial port, and I see that it tries to start sending from the LEDs on the board. During the sync process, however, the function returns timeout errors and the upload fails.

I just tested on a chromebook using an Uno board, and it works fine with an Uno.

I have read that there are a few differences in the usb connection to the redboard.

Does anyone have an idea of how I might be able to tweak my plugin?

I have already tried increasing the timeout from 400 to 600ms but no joy.

Thanks for any help.

Trevor