Check iPhone Bootloader and Firmware Version

Please refer to this article

download sendmodem from there

Here is my iPhone's Output

# sendmodem "AT+XGENDATA"
Sending command to modem: AT
------.+
AT
OK
Sending command to modem: AT+XGENDATA
-..+
AT+XGENDATA
+XGENDATA: "    
",
          "DEV_ICE_MODEM_04.03.13_G",
"EEP_VERSION:208",
"EEP_REVISION:1",
"BOOTLOADER_VERSION:3.9_M3S2",1,0

OK