B209 was a regional firmware update for Germany & other European countries, officially released by Huawei in July 2014.
It fixed the dangerous Heartbleed bug and brought some other minor optimizations (e.g. improved RAM- and battery usage).
It's official package name is Y300-0100 V100R001C00B209_Firmware_West European_Channel-Others_Android 4.1_EMUI 1.0_05011KYP
.