Both Sims are not detected after update Lenovo A390 with the latest ROW firmware I have format my Lenovo A390 and update to latest ROW firmware version A390_ROW_S316_130730.
Everything work fine but sim cards not detected. At down of the lock screen shows Invalid IMEI. In the status bar sim also not showing. 


Model number     :- Lenovo A390_Row 
Android version  :- 4.0.4
Baseband version :- A390_MB_PCB_V1.0
Build number     :- A390_ROW_S316_130730


IMEI are Unknown

Wifi also work fine. What should I do now. Please help
I have solved the problem myself. Reason of the problem was Invalid IMEI number. What I did is set the valied IMEI for Sim. 

Steps to Change IMEI Number of Your Android 


Write the following in your dialler – *#7465625# or *#*#3646633#*#*.
(*#*#3646633#*#* this work for me)
Click to Call pad or connectivity options. Find out CDS information
and tap on it. Check out for Radio information. If
you have dual SIM, there will be two options for you, select the one which you want to go with.
Now to change IMEI number follow 
AT +EGMR=1,7,”IMEI_1”


Replace IMEI_1 with your IMIE. For example : AT+EGMR=1,7,”8600XXXXXXXXXXXX"


And click to send. 


Changing IMEI number is illegal but it may help you to get your phone back. Make sure to use  "YOUR" phone IMIE number (15 digit code ) written in the backside of the phone (mostly Under the battery)

EDIT

For Sim 2 need this insert “AT +EGMR=1,10,"IMEI_2”