Can't find my way through the many guides, could use a lil'bit of help

[Rivyan]

Hey lads!

I am trying to root my HTC One M8, so I can get a finer options for sounds (and other advantages, aswell). I found this post https://forum.xda-developers.com/htc-one-m8/help/how-to-root-htc-one-m8-android-6-0-t3420748 about rooting an M8 with android 6.0. I'm writing this post, because I don't want to screw it up, so it seemed better to ask for help, before I do something stupid and brick my phone. I tried searching the forum, but after opening like 10 tabs, I lost my way. (I am using Windows 10, legit)

So, this is what I did:
1) Downloaded the Android Studio.
2) Via the studio, I downloaded the 6.0 platform.
3) And here is my first block: tried to install ADB, via Universal Naked Driver: I downloaded the ZIP, unpacked it, and while my phone was connected, tried to update its driver via the Device Manager. I got a message that it's up to date, and even tho I picked the 'I have disk' option, it wouldn't do anything. Now, I downloaded MiniADB v_1031, and when I ran the cmd from here, I could see my device with adb devicelist. I also installed HTC Sync, and used the driver installer from adbdriver.com, and it showed that I have the needed driver.
4) From the folder where I have unpacked miniadb, was able to run adb devicelist, and adb bootloader reboot aswell. But from that point, even tho I enabled developer options in my phone, and USB debugging aswell, my PC can't see the phone, only if I reboot to normal mode. When I am in fastboot USB, adb devices just says 'list of devices' and a blank line under it.
5) Tried to unlock the bootloader, and I got my identifier token. I am good to go then, I have every driver what I need for continuing from here?
5)b) Edit: Seems like I managed to unlock the bootloader.
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So if I understand it well:
From now on:
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6) Download the EU version of TWRP 3.0 from here (I am from the EU)
7) Use the cmd 'fastboot flash recovery twrp.img'
8) The site mention a key-combo to prevent the phone to go back to basic recovery, do I need this?
9) Do a backup via TWRP (is it going to be a simple option in the recovery? How big SD card do I need? Atm, I have 12 Gb one, gonna buy a 128 one in like 1-2 month)
10) Copy the SU.zip to my SD card and use a flash option in the recovery?

Sorry for any dumb question, I'm kinda scared bricking my phone, but at the same time, I would like to get the advantages of rooting.

So anyway, did I miss out on any step, screwed up anywhere, or smth like this?

Any help is much appreciated!

 

[redpoint73]

My comments to your steps/questions:

4 and 5) adb and fastboot are two different, but related interfaces. Don't feel bad, it's a common mistake to mix up the two (adb and fastboot). You'll really only need fastboot for rooting the phone. The step to "adb reboot bootloader" in the TWRP install instructions can alternately be done without that command, using the button combo to get to bootloader. But I think you must have figured that out by now, if you managed to unlock the bootloader.
In summary,
adb: needs USB debugging on in phone settings, only works when phone is booted in OS or alternately when booted into TWRP (last part obviously doesn't help, if you haven't installed TWRP yet).
fastboot: only works in bootloader-fastboot mode (will not work in OS or TWRP), does not need USB debugging on in phone settings.

6) The options are for download mirror locations (US vs. Europe - literally just where the download's server location is located), and do not specifically refer to different TWRP versions. The same TWRP version works for both US and Euro M8 models. What you downloaded is fine, so my comment is just FYI.

8) No, you shouldn't need this. I believe this comment refers to newer devices, and not specifically to the M8. I literally think the TWRP team has copy/pasted this statement to instructions for every device on their website, whether it applies or not.

9) Yes, this is a clear option once booted into TWRP recovery. Literally, on the TWRP main screen, you will see a big button labeled BACKUP. Tap it, and select system (ROM or OS) and boot.img, and also backup data if you like. The backup of system and boot.img will take around 2 GB. The backup of your user data might be much more, depending on your apps, etc. Although, if you just unlocked the bootloader, the phone should have been wiped, so you may not have much (if any) user data to backup.

10) While SuperSU 2.76 (mentioned in the thread you linked) should work fine, I would suggest using the latest stable version 2.79 from here: https://forum.xda-developers.com/apps/supersu/stable-2016-09-01supersu-v2-78-release-t3452703

Just put it on the phone, boot into TWRP, select INSTALL, select SuperSU 2.79.

---------- Post added at 12:42 PM ---------- Previous post was at 12:37 PM ----------

Sorry for any dumb question, I'm kinda scared bricking my phone, but at the same time, I would like to get the advantages of rooting.

Don't worry, you won't brick the phone (permanent damage) by unlocking the bootloader, custom recovery, root, etc.

Anything you do is recoverable/reversible, even if something goes wrong (especially if you make a TWRP backup of your current stock ROM before rooting).