Lenovo K3 Note (K50-t5) may lost IMEI by improper use like upgrading wrong ROM,using wrong flash tool to install new ROM and so on. This mistake will cause calling is impossible and lost Warranty from the manufacturer.
Some user may solve this problem by using mobileuncle app to recover IMEI in root permission. But it will not work on lenovo K3 Note k50-t5. If you want to solve the problem permanently, you need to read the article on http://bbs.ydss.cn/thread-543013-1-1.html by google translator.
The tool from this article are:
1. Lenovo smartphone driver: ;
2. SN Writer tool:;
3. K3 note MTK6752‘s file for IMEI:
These IMEI files is based on official K50-T5_USR_ST1512_5.495.1_1503191926_MP6V3_CN ROM. If needed, you need to flash the ROM to install IMEI all right