If you download our latest UI DD2.0 from the website, there is BNO055 FW version 0.3.2.0 embeded inside.
You can also use DD2.0 to upgrade the FW of BNO055.
The FW file you download from our website with DD2.0 link is a patch for DD2.0.
After execute the exe file, you will get BNO055 latest FW (.hex) file under "C:\Program Files\Bosch Sensortec\Development Desktop 2.0\Firmware" which is under the installation folder of DD2.0.
If you wire out the nBOOT_LOAD_PIN (pin 4) to host, then it is possible to upgrade FW also via the host interface.
We are planning to release a example code for FW upload and the application notes.
But in current phase, you still need to contact your local support channel to get those things.