I sent an e-mail to Silabs and this is what they mailed back:
Sorry for the delay in answering your email. The problem you are seeing is probably due to flash corruption which means that the contents of the flash has been accidentally modified. In this case you should reflash the device.
To upload again the flash with the correct firmware you will have to do the following:
1. download the latest version of the FM Radio RD firmware from our website:
2. connect to the USB FM Radio (you need an USB Debug Adapter for this):
- on the debug adapter's connector, the pin 1 is the one corresponding to the red wire or to the arrow on the connector
- take the FM Radio board out of its casing
- near the MCU are three holes which are the GND (written next to it C12), C2CLK (written R18) and C2DAT (written C17). These holes can be used to connect to the device using the debug adapter as follows
- connect pin 9 of the Debug adapter to GND (hole with C12)
- connect pin 7 of the debug adapter to C2CLK (hole with R18)
- connect pin 4 of the debug adapter to C2DAT (hole with C17)
3. connect the USB FM radio to the USB port and the USB Debug Adapter to another USB port
4. open the silabs ide and press the connect button. The device should get connected
5. extract the zip file you have downloaded
6. open the F320_FM_Radio.wsp project with the silabs ide
7. compile the project and download it to the device.
8. disconnect all wires and everything should be working properly
You will need the full keil compiler to compile this project since it is bigger than the standard 2K. In case you do not have the full keil compiler, I have attached the compiled hex file which can be uploaded to the MCU as is.
Please let us know if you have further questions.
So they want me to buy a programming debug tool and reflash the USB radio. Surely when you buy a product you shouldn't have to do this?