TinyOS - Utah-WiESEL/wren_wsn GitHub Wiki
This platform is fully compatible with TinyOS. Below is the link to the repository which contains the ported TinyOS code for the WREN.
http://wiesel.ece.utah.edu/redmine/projects/tinyos-prod
The installation is slightly different on the WREN due to the difference in BSL. To install a user application on the WREN, the i2cbsl must be used and followed by the Bus Pirate's port.
e.g. make wren install,0x00 i2cbsl,/dev/ttyUSB0