Here i post a guide for those on china rom want to flash global rom. if you're on fake rom or your phone comes with global 9.2.3.0, i suggest you go testpoint flash China rom dulu.
1. apply unlock approval. :
http://en.miui.com/unlock/ wait for approval sms.
2. download mi unlock tool, miflash tool and mi PC suite and install in your PC. preferably if you have at least a windows 8 64-bit and above.
3. download and install plexVPN from playstore in your phone. turn on plexVPN and select a China server. any city is fine, but most ppl choose shanghai or beijing.
4. activate developer options in your phone. turn on USB debugging and under "unlock" tab, bind your mi account. same account as the one you key in when apply unlock.
5. after successful binding, turn off your phone, then press power + volume down button together to enter fastboot mode.
6. open mi unlock tool, connect your phone to PC using USB cable. the tool will detect your phone and "unlock" button should be visible. press unlock, and it will give you an error message that say something like "failed to unlock after 360 hours". take note of your date and time when is 360 hours gonna end. unplug the phone from pc, turn off and on as usual. shut down your pc. there is nothing else for you to do for now, wait until 360 hours is finished. do not connect the phone into mi unlock again as long as the countdown is not finished, otherwise your countdown might be restarted.
7. after the 360 hours is completed, phone enter fastboot mode, open mi unlock tool, connect your phone to PC again. the tool will detect your phone and "unlock" button should be visible. press unlock. if there is no other problem, the unlock will be successful.
8. restart your phone, go into developer options and under the "unlock" tab see if the status is "unlocked". if yes, congratulations you can now flash global rom 9.2.6.0.
9. follow all the instruction given in the fastboot tutorial EXACTLY. the fastboot rom download link is listed in there as well.
http://en.miui.com/a-234.html