[Sony Cross-Device General] gonewild87:
HOW TO CHANGE XIAOMI MI2 RADIO BAND

My 3g didn't work anymore after messing up with radio band by entering the testing mode (*#*#4636#*#*) --> phone information --> select radio band (3 dots in the right corner) --> clicking on usa band (i'm in europe).

I got this situation:

but without the euro band, only with aus2 and usa bands (the pic was taken after i solved this issue)

I solved it after struggling a while for a solution. Here it is:

YOU MUST BE ON WHATEVER MIUI ROM BECAUSE DIAG MODE DOESN'T WORK ON CUSTOM ROMs (tested with miui 6.1.14 developer)

1. Download this zip (just click): Google it as it's banned from xda for the ability of imei change

2. Extract it and install QPST from that zip

3. Get into Diag mode on the phone:

- open dialer

- enter: *#*#717717#*#*

- you'll see a toast "diag mode enabled"

(note: to disable diag-mode enter the same code again)

4. Download the driver from here. There is also QPST program inside.

5. Connect your phone to pc via usb

- once diag mode enabled, you will see the Device Manager from PC like this (only with MI2 other then mi note lte)

- You'll see very much devices (MI2 written multiple times) without driver installation.

- Right click 'MI 2' one by one and install the driver you just downloaded (xiaomi_mi2_diag_driver.zip didn't work on my win8 tablet, so i had to install the first 3 folders in the mega link - 206208, 4223 and a761 - i don't remember if all worked but i used these ones)

- Only 3 of the devices will install, it doesn't matter we don't need the others

- You will see this:

or this in my case (modem didn't install properly, it just installed hs-usb mdm and msm diagnostic + hs-usb nmea):

Keep in mind "COMxx" (xx are the numbers)

6. Press Windows start button and navigate to QPST -> QPST Configuration

7. Open the "QPST Configuration" program, click on tab "Ports", then on "Add new port" and in "Port" type in your "COMxx". In my case it's "COM39". In "Port label" it could be anything you want. In my case I typed in "MI2"

- you should see below straightaway (only with SURF9615 other than MSM8974 - and also COM39 in my case):

8. Now select the QPST Start Clients > Software download > Backup > Start. Wait until the status says 'memory backup completed'. This saves a backup copy of your phone's stock NV memory to your computer in case you need it later.

9. Navigate in your pc to Program files/Qualcomm/QPST/bin and open RV_NV_Manager.exe

10. press on settings -> Comport and choose your COM port (COM39 in my case).

11. Press on file -> read from phone

12. Wait patiently until it is finished. Now pay attention!

13. Go to line 1877, click it and copy the decimal number on the right side of the program. (right click - copy)

14. Go to the place where you extracted the zip from the first step and start mzTool_1.2.1a

15. On the left side you will see "Input radix" - press decimal there.

16. On the right side you will see "RF BC CONFIG" - paste your previously copied number from the RV_NV_Manager.exe there.

17. You will see now what bands you are able to use on the bottom of the app in "Bit information"

18. Switch tab to "Band Preference (NV Value)"

19. In there select all GSM bands and WCDMA bands. This place is really a field of testing. In my case I selected all of GSM and WCDMA. I wouldn't suggest you to do anything else in here unless you know what your'e doing.

20. After you're done choosing what bands you want, copy decimal number from the bottom right (I copied the Hex)

21. Remove all commas from that number ( "," ), so it would be just a bunch of numbers without anything else (no spaces).

22. Open RV_NV_Manager.exe from the point you left it (step 13) and paste your new number without commas "," there.

23. Press on "write NV" just over the number and then press on file ->write changed NV to the phone.

24. Disable diag mode:

- open dialer

- enter: *#*#717717#*#*

- you'll see a toast "diag mode diasbled"

25. Reboot the phone

26. Flash a custom rom (I used cyano 5.1.1 rom from [MENTION=6770252]bugers[/MENTION]), because if you type *#*#4636#*#* on miui rom you cannot select radio band)

- enter the testing mode (*#*#4636#*#*)-> phone information --> select radio band (3 dots in the right corner) --> change to whatever you need (euro band in my case)

3g restored!

thanks to [MENTION=3530648]m11kkaa[/MENTION], [MENTION=4300205]olokos[/MENTION] , [MENTION=6575281]GeorgeZZzz[/MENTION]