Please use the below link to find the files for your Zong MBB Device.
Supported version:
21.323 01.00.306
Zong bolt Plus Model – E5573cs-322
or
Huawei E5573cs-322.
After this unlock, Zong bolt Plus Model – E5573cs-322 will work on all networks.
I have tested Jazz, Telenor, Ufone and Zong SIMs on this device after unlock.