this is a general method to fix invalid imei number on media tek (mtk devices).
steps:
1. make sure your phone is rooted (check the technology category for any root method that might work for you)
2. you will need a root Explorer or Es file manager (with root Explorer enabled).
3. IMEI information is stored in /data/
nvram/md/NVRAM/NVD_IMEI/
MP0B_001 locate this file and edit it to your original imei number. that's all.
