try use mi PC suite and phone enter the recovery mode then go to miui website to download the OTA ROM, then on the R.Flash there shift+left click to choose the ROM, then wait it to update finish.

If cannot, need to enter qualcomm Emergency Download (edl) mode to do the flashing by using Mi Flash and fastboot ROM with perform of full wipe (it's very important, if not u may soft bricked ur device). The command to enter edl mode is:
adb: adb reboot edl
fastboot: fastboot oem edl

But then the unlocked edl, locked bootloader is only available on the earlier version of MIUI (in fact is the emmc_appsboot.mbn this file doing the job), I dunno Redmi Note 3, but in Mi 5 on 7.3.1.0 and onward they locked the edl as well so u can't enter edl anymore unless u fastboot flash back the older version of emmc_appsboot.mbn which is consist in older version of MIUI (like 7.2.4.0 which no longer can be download in the miui website anymore) only u can enter back the edl mode.

How I know this is due to yesterday I soft bricked my newly bought Mi 5, I bought AP set and the MIUI pre-install is the unofficial version/China carrier customized vrsion (7.2.4.0.0) with lot of bugs so I was using edl mode to flash, but then I forget to press flash all, end up stuck in mi logo and only can enter recovery/fastboot mode, also can't flash OTA ROM in Mi PC suite also in recovery mode. So I was spending few hours of internet search and end up finding that fastboot flash the emmc_appsboot.mbn (fastboot flash aboot emmc_appsboot.mbn) can reenter back the edl mode, so I tried both 7.3.1.0 and 7.2.4.0 and end up 7.2.4.0 of emmc_appsboot.mbn does no lock edl in fastboot.

So that's save my phone and now I'm running Global 7.5.1.0 , but the pay is I slept at 5am

This post has been edited by sss2sssss: Jul 3 2016, 08:16 PM

Plug to ur PC and see got any new device or Qualcomm driver with COM port come out bo?
And u need to install Mi Flash if u dun have driver
it's normal for black screen since in edl mode it dun show anything

This post has been edited by sss2sssss: Jul 3 2016, 10:36 PM