[Xiaomi Mi 4C] akrai:
First of all, sorry for publishing an uncomplete guide, im traslating my own full spanish guide and at the same time making it more complete and better, and i decided to do it this way, publishing progressively

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SECTION 1: Android argot summary

I put this link here so any new user in the Android rooting/flashing world can learn the classic words used

http://www.talkandroid.com/guides/beginner/android-rom-and-rooting-dictionary-for-beginners/

Note: in bootloader it says that the phone comes locked, which in our case usually is not the case, but anyway you can know if your phone is locked just by trying to get into the fastboot mode, if you can't get into it, its locked.

An Android phone's disk is virtually splitted in several partitions, like a computer, but not exactly the same because even when your phone has a lot of partitions, you will only see one if you didn't rooted your phone, or two if you did, and the partition where you have your photos and the rest of your personal downloaded things is named sdcard (yes, is a legacy of Android, even when we don't have sdcard), or even in some ROMs is called userdata or something like that; another partition is system, where the ROM itself is, is like the installation of Windows; another is data, where the config files of the apps are stored when you start using them; another is cache, where the cache of the apps are (you can think of it like the apps are compressed always, and to run faster they descompress themselves in that partition), and there are two of those partitions: dalvik cache and cache; also bootloader, which is like the BIOS of the computer, is the most basic program that makes possible the phone to boot, and also it is not possible to edit it, it is not writable, it is this way so that

you wont never be able to hardbrick your phone

(which means that you can literally drop your beautiful phone into the trash, no way of fixing it), like it was in older phones, and also in this partition you also have the fastboot mode, which i'll explain later; and the last one im explaining (there are more but you probably wont never know about them) is recovery, where there is installed the recovery, and what is recovery? is a tool which is by itself an entire operating system, but made specifically for "developing" purposes, mainly for flashing ROMs and making backups of the entire partitions. We have two recoverys for Mi4C, the Mi Recovery, which comes by default with your phone, and is very limited, mainly you can only flash Xiaomi's official ROMs, and the TWRP recovery, which is the absolutely most popular recovery, and strongly suggested to use, no disadvantages at all. Also know that, like in Windows you can't format the very own Windows partition and you must use and external tool, which would be the Windows installation CD program or something like that, here we have the recovery, you can't flash or wipe using Android, you must be in the recovery mode.

So as I said, the bootloader is readable only by security, and it includes the fastboot tool, so you must know to lost the fear of this world, that YOU WON'T BE ABLE TO HARDBRICK YOUR PHONE, you will always have fastboot to reflash a complete Android ROM (which requires a computer and a fastboot ROM, which is different than a flashable ROM. You will use a fastboot ROM in the first flashing tutorial, more bellow)

What is Fastboot? Basically is a tool which acts like a server in the phone, and as a client in the computer, and is made mainly to make basic things to the phone, like flashing partition images (included in the fastboot ROMs, extension of each one is .img) or read the locking status of the bootloader.

What is a locked bootloader? In our phone, is a bootloader that only allows you to flash official xiaomi roms, but as xiaomi don't offer a global version of miui for our phone, the only official rom is the chinese one, which appart than having only english and chinese languages, is very bloated of chinese apps, so is very recommended to unlock the bootloader and flash any other rom of your desire.

How to access fastboot? First, shut down the phone; second, press at the same time the Power and the Vol - buttons for a few seconds, there should appear in the screen a Fastboot logo. Note that the phone may automatically shutdown if no connection is made with a fastboot client in a computer in about 10 seconds after entering fastboot mode

How to access recovery? First, shutdown the phone, then press at the same time power and vol+ for a few seconds

What is ADB? Is a tool that works the same way as fastboot (phone and computer connected), but instead of being in bootloader, it is inside of android, and instead of doing essential work for the phone, it does more practical things like transfer of files, but you will probably not use ADB at any time. Also, for transfering files you wont use ADB, which like Fastboot is a command line tool only, but you will use MTP, which is the media transfer protocol, the graphical way of transfering files, in your computer it will appear like a classical external drive, but in Windows the icon will be like an iPod.

Note before starting the flashing tutorial: go to Settings > (bottom) About phone and look at the MIUI version, MIUI version numeration is supposed to follow a date (the date of release) except the first number which could not be the year, it could be 5, 6 or 7, so a correct numeration would be for example 7.2.1.0 (there is always a 4º number which is always 0 if do remember well). The thing is that when you buy the phone to a reseller, is very usual that they flash their custom MIUI rom which comes with international language, its fine, but it also comes with spyware and adware everywhere. Those roms usually comes with a version numeration of strange repeated numbers, like 77. 87. 55. 99., remember that the first number always must be 5, 6 or 7. In case that you have preinstalled this rom, i suggest you strongly to follow the guide fully, including the clean flashing with fastboot rom

Note 2: you need to have the bootloader unlocked in order to continue, please read the unlock tutorial below

Note 3: this guide supposes you have Windows. If you have Linux or Mac, or you have any problem, please ask here

Note 4: for this guide we are going to use a Drive folder shared with a spanish mi4c community, so file names may contain spanish words but shouldn't be a problem. Sorry for the inconvenience, but it's for ease purposes. Drive link: https://drive.google.com/folderview?id=0B3N1d6szT1RYWkNET0pEbWhud3c#list

SECTION 2: Flashing guide (part 1/2: cleaning)

We are going to flash the 7.1.4.0 fastboot ROM in order to update as much as we can all the firmware (drivers of usb, modem, camera...), clean all from the weird ROM of the reseller and all of that without locking the bootloader.

Please, charge your phone first to at least 50%. Also, this process will erase all your personal data in the phone, backup all you need before.

1. Download the Fastboot 7.1.4.0 ROM (for example, here https://drive.google.com/folderview...RUR3WkE&tid=0B3N1d6szT1RYWkNET0pEbWhud3c#list ) Also download the 2 other files from that link.

2. Go to the root directory of your computer drive, usually C:\ and create a new folder with a simple name without special characters, neither spaces (for example, flash) to avoid problems in the process (at the end of the guide you will be able to delete that folder).

3. Go into that folder and extract the ROM, you must be able to see a folder named images and files together (Note: maybe you could need 7-Zip to extract it)

4. Now Install the other 2 files you downloaded. Then, reboot the computer and poweroff the phone

5. Exec the MiFlash tool, copy the path of the folder (for example, C:\flash) and paste it in the MiFlash tool

6. Now go to advanced

7. Click on Browse for Fastboot Script and choose flash_all.bat (if you are not able to see the file extensions, you should enable the viewing of file extensions (google for it))

8. Now put the phone in Fastboot mode (being it powered off, press power and vol- at the same time for a few seconds until the Fastboot logo appears) Note: to exit this mode, just press power for a few seconds

9. Now connect the phone to the computer with the usb cable (adaptors may give problems) and press on Refresh in the MiFlash tool in order for the phone to appear in it

10. Press on Flash, wait for the green bar to finish (could last minutes, just wait, if error is shown, post it here, if more than 1 hour and nothing changes, maybe is the computer, maybe is the cable, maybe is your bad luck). Done this part of the guide

Credits for this section of the guide

SECTION 3: Flashing guide (part 2/2: Flashing at last!)

1. (Downloading) Enter the Drive folder posted above and download the TWRP zip, the ROM of your desire (see below for reading more of every ROM), the google apps (MIUI already comes with preinstalled google apps, not needed in that case; also, you can download the google apps at opengapps.org and picking ARM64 and 6.0 android (or the version that the ROM you are choosing is, probably 6.0), and picking pico or nano is enough, comparison table here https://github.com/opengapps/opengapps/wiki/Package-Comparison ) and the supersu (only if you want root, anyway you can flash supersu at anytime without needing to wipe or anything, is easy). If you didn't do the part 1/2 and you need the Windows drivers, you can download it from the Drivers Windows folder, install it and reboot the computer.

1.1 (Uncompressing) Unzip the TWRP file in a sort path from the root folder, like for example in C:\TWRP (at the end of the guide you can delete this). You should see a file called recovery.bat (if you can't see extensions, google for enable it), it is for the step 3.

1.2 (Testing MTP) We will need to use MTP while we are in the recovery mode, so first let's test it in Android. While the phone is fully booted in Android and in the launcher screen (if starting for the first time, skip all the tutorial with whatever info), plug the phone to the computer, and in the phone swipe down the notifications bar, you should see a notification saying something of MTP or wired connection, activate MTP. Now in the computer, open My Computer and you should see Mi4C there, open it and try to navigate and create a folder, if all is ok, it works. If you are not able to create a folder o transfer any file from your computer, do not continue until this is fixed.

2. (Fastboot) First, keep the TWRP folder open and the recovery.bat file visible. Unplug the phone and put it in Fastboot mode (power it off, then Power and Vol- for a few seconds)

3. (Recovery flashing) Just execute the recovery.bat file (double click) and press a key if it asks for it (there should appear a green window with text). Done, recovery flashed (read text to see if everything is done). Now with TWRP installed, you won't need anymore (you shouldn't) the computer for using fastboot, now only for transfering the ROM files to the phone to use it from the TWRP.

4. (Wiping) Now let's boot into Recovery mode (TWRP in this case), two ways for it: you can Power and Vol+ while it is powered off, or you can boot Android, go into Settings, About phone, updates and in the 3 dot menu, there is a button for booting into recovery.

Note about the first TWRP start, it should appear this screenshot

Just press on never show again and swipe. Now, in TWRP, enter Wipe, select all partitions and wipe them all, it should appear an error about usb otg, doesn't matter, wipe is done correctly. Now you need to reboot into Recovery mode again, needed when wiping partitions another than cache or dalvik cache (if you don't reboot now, it won't let you flash), so press the mid button in the navigation bar to go to the main menu, and enter in Reboot > reboot recovery. If a message of "no OS installed" or "install supersu" appears, say no or ignore

5. (Flash!) Now, with the phone plugged, MTP should be working, so now you have to transfer the ROM, gapps and supersu files (gapps=google apps; gapps and supersu if needed as i explained in step 1). Now in the phone, press install, select the ROM, then add zip, select the gapps, add zip, supersu, and then swipe, a minute later there should appear a reboot system (android) button and the wipe cache button, first press wipe cache button, do it, and then reboot system.

Congratulations, now you can consider yourself a h4k3r, next step hacking into NSA maybe or something? Wait for the guide

From now on, flashing will usually consist in downloading the rom file from the phone (or from the computer and then transfer to the phone) and with the same gapps and supersu files downloaded above, you can flash, and then wipe cache. This is a dirty flash, only do it if updating a ROM, if going o another type of rom you must clean flash, which is done by first wiping all partitions as done in step 4 (note: all personal data would be lost, backup with titanium backup for example, and transfer all files to computer)

SECTION 4: Summary of ROMs available to our phone

MIUI: the ROM that comes with the phone, made by Xiaomi, full of features, loved by ones, hated by others

-MIUI chinese: the original official Xiaomi one, only in english and chinese languages, and comes with preinstalled chinese apps. Two variations: stable (released like once per month) and weekly

-MIUI .eu: modified version of the chinese, removed preinstalled chinese apps, a lot of languages included. Also comes in stable and weekly versions.

CyanogenMod: is a proyect which purpose is to make the full ROM open sourcered, and include more features than the official Google Android ROM doesn't include.

-CM from Kumajaya: most popular edition for our phone, this guy is doing a very good job with the kernel, making the ROM very stable and battery efficient.

-CM from Team Superluminal (TSL): they were the first to bring us CM, is not open sourcered (or at least is not their main job, as opposed to kuma) but is pretty stable, more recommended for noobies, kuma is more for staying up to date frequently

Resurrection Remix: a ROM that brings together a lot of different ROMs, unifying a lot of features. In Mi4C is a bit unstable for now, but is a matter of time.

Moke

SLIM

And I add here a link for a nice unlocking bootloader guide http://xdaforums.com/mi-4c/general/guide-unlocking-mi4c-bl-verification-t3336779