My recent experiment in flashing the Chinese firmware for my Lenovo Tab A7-30 to the European version resulted in an error in the IMEI or International Mobile Station Equipment Identity ; a 15 digit number that is unique to the device. Every time I input *#06# is brings the message INVALID IMEI and without a valid IMEI, your device will not be able to make calls, send text messages and other simple communication over the network. Now, to be honest, this is a side effect of flashing I did not consider. Fortunately, restoring the number is not that difficult and thanks to instructions from Plus Droid ( www.plusdroid.com ) I restored mine. For my device, the IMEI number was printed on the box so it was relatively easy to restore it. The first thing is to open the device in engineering mode. This is done with the following code *#*#3646633#*#* Get into Engineer mode by using *#*#3646633#*#* Then swipe to Connectivity and ...