The little black zero ohm resistor on the right is to be removed to perform the out of band mod. Once you remove it your radio will reset the next time you power it up so back up your memory. I use the FTBVX8G software. Pre mod mine showed up as a USA2 after the mod it showed up as a USA3. As can be seen on the left there is a small switch which I am calling the "mystery switch". I played with it before and after doing the out of band mod and noticed no difference. It came switched to the right. When I switch it to the left the radio does nothing. It will not power up or recognize that the power cord is plugged in. With the battery removed if I switch it to the right, plug in the power supply, power on the radio and then switch it the radio will be on but frozen. No buttons will respond and it will not tx/rx. Sometimes it would reset it's self after a few seconds to minutes and be operational with the switch to the left, I did not notice any change in operation other than when the power cord is removed and then reinserted or the battery is installed it will no longer power up or do anything. If I remove all power switch it back to the right (default setting) and re apply power then it seems to be back to normal. Any ideas what it may be used for? My thoughts are perhaps putting it into mode for firmware upgrade over the serial port?