I know there have been a few posts on this. But I just completed the update with tech supports help as their online instructions need updating.
Link to firmware aXXera Audio - Product Firmware Updates
1. Place the 1st of the 2 files (MPEG) on your USB. Insert it and do the installation. Remove the USB, delete that file from it and place the 2nd file (MCU), reinsert the USB and to the 2nd installation.
2. Upon installing the 1st file you get a display they tell you about. It says 'erase and program' and has 2 selections; media and cancel. It selects the cancel and sits there. What they do not tell you is you have to select 'media'. Once done it will do the install quite quickly. When you do the 2nd file you will have to select 'system' for it to finalize the install.
3. When they talk about pressing the reset button which is a pin hole in the front of the unit. The tech said to press the one above the USB, not in the front top of the unit.
After knowing these few things the installation was quick and easy. Does the radio work better Ö we will see.
Hope this helps.