What are all these firmware files for the Sterling-LWB5+?
The Sterling-LWB5+ supports the use of two different antenna configurations. That is single antenna (SA) or antenna diversity (DIV).
It also supports the usage of two interface configurations. That is SDIO for Wifi and UART for Bluetooh on the one hand and USB for both on the other.
For each interface combination there is a possible antenna configuration, hence 4 firmware files.