With this app, you can easily backup your EFS (IMEI) and modemstpartitions. You can backup in Internal and External sdcard thatbest suits you. This app backs up your EFS in two different typesand in two files. First backup is in .img format and second is in.tar.gz format. Also,there are two backups of EFS at same time. Onebackup is named as efs_vinny.img and second in efs_(date).img. Thisway,you will be 110% sure and risk free. Also, there's Successfuland failed status of backup.
Note-You can request your model if it's missing in the list.