This was not made by me all credits go to ethan2k the text below is exactly what he posted on miui forum hope this helps.Hi All,
After 3 days of researching and semi bricking my phone, I have now worked out how to properly unlock most bands of LTE for international use!
NOTE: This guide is for Xiaomi Note Pro 64gb China version only.
***** THIS GUIDE WILL UNLOCK THE FOLLOWING BANDS: 4G bands: LTE band 1(2100), 2(1900), 3(1800), 4(1700/2100), 5(850), 7(2600), 8(900), 17(700), 20(800), 28(700) *****
First of all download this package. I have zipped it up into seperate folders.
https://drive.google.com/file/d/0B-0...ew?usp=sharingThis driver pack only works on Windows 7!! Win 8 and 10 are not working!
Here goes:
1. Unzip the package into anyplace on your PC
2. On your phone type in: *#*#717717#*#* This will enable Diag USB mode for your phone
3. Before you plug your phone in, enable USB Debugging
4. Plug in USB cable into your phone, then go to Device Manager -
* Update the driver for Device Manager --> Ports (Com & LPT) --> Qualcomm HS-USB Diagnostics 9025 from the Zip folder: "1. Xiaomi Diag Driver"

It should now look like this, remember what Com Port the Diagnostic 9025 is using, in my case its on COM11.
5. Install "2. QPST v2.7 Build 4.11" from zip package
6. Install "3. QXDM-3.12.714" from zip package
7. Open up QPST Configuration
8. Go to Ports tab - By default it should have found the phone and auto added the port.
9. Leave QPST running in background
10. Open up QXDM Professional
11. Go into Options --> Communications --> Enable the Com Port your phone is running on.
12. Back to QXDM main window, in the "View" drop-down menu, select NV Browser

13. Now the fun part begin
Inside the NV Browser window, scroll down and click on line 01877 (rf_bc_config)(1); click the Read button(2), save somewhere the original value in case something goes wrong (inside notepad or anything), replace Input value with 3460734838925427584(3) and click on Write button(4).

14. Inside the NV Browser window, scroll down and click on line 00946 (band_pref_16_31); click the Read button, save somewhere the original value in case something goes wrong (inside notepad or anything), replace Input value with 0x0FF8 (please don't be an idiot and don't edit the empty one with "nam" in the name) and click on Write button.
15. Inside the NV Browser window, scroll down and click on line 02954 (band_pref_32_63); click the Read button, save somewhere the original value in case something goes wrong (inside notepad or anything), replace Input value with 805765120 (please don't be an idiot and don't edit the empty one with "nam" in the name) and click on Write button.
16. 10. Inside the NV Browser window, scroll down and click on line 00441 (band_pref); click the Read button, save somewhere the original value in case something goes wrong (inside notepad or anything), replace Input value with 0x380 (please don't be an idiot and don't edit the empty one with "nam" in the name) and click on Write button.
17. Inside the NV Browser window, scroll down and click on line 06828 (lte_bc_config); click the Read button, save somewhere the original value in case something goes wrong (inside notepad or anything), replace Input value with 2061853925599 (please don't be an idiot and don't edit the empty one with "ext" in the name) and click on Write button.
18. On your phone type in: *#*#717717#*#* This will now disable Diag USB mode
19. Reboot your phone and its all complete!!!