Clone phones often have maliciously modified AT command sets. Proceed with extreme caution. Often, clone SPD phones require a different code: *#*#3646633#*#* (MediaTek code) even though they run an SPD chip.
For or UNISOC Android devices, "IMEI repair" typically refers to restoring an Invalid , Null , or 0000 IMEI that occurred due to software corruption, such as a failed firmware flash. Common Engineering Mode Codes spd android imei repair code
For many older or basic SPD-powered devices, you can repair the IMEI directly through the dialler: Clone phones often have maliciously modified AT command sets