[Q] How to root HTC One M8 without losing OTA update ability? - AT&T HTC One (M8)

Hello,
I am not new to the process of rooting, unlock bootloader or flashing ROM. But, this is the first time that I need to root a HTC phone, the HTC One M8. I don't usually care much for stock ROM, but this is my girlfriend's phone and I think stock ROM works best for her. It is more stable, even though it will be a bit slow and has a lot of bloatware. I plan to root it then manually go in and disable most of the bloated apps. Then, I will install Xposed Module and add some useful modules. However, the release of Lollipop is around the corner. I want to know if rooting it will affect the ability of doing OTA upgrade.
Base on what I have read, in order to root, you have to unlock the bootloader, then replace the stock recovery with custom recovery like CWM/TWRP, then you flash the supersu.zip file to grant root permission. I am familiar with the process, but I am a bit confused at this part. Since we use a custom recovery to flash the supersu.zip file, it is more likely that OTA upgrade will fail since most OTA upgrade rely on stock recovery.
1/ Then, how do I upgrade to Lollipop 5.0 once I have rooted the phone?
The current ROM is Kitkat I think.
2/ I mean, is there a stock recovery file that I can flash back to replace the custom recovery once the phone has been rooted? or the OTA process will work with the custom recovery, which is very unlikely in my opinion.
3/ Also, once I have upgraded to Lollipop, I can do the same process to gain root again, (flash custom recovery, then flash supersu.zip to gain root). Is that correct?
4/ Is there any other method of gaining root without losing OTA update? As long as I don't have to wipe everything and restore it for every OTA update. I am fine with it.
Please let me know. Thank you all for your help.

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After you root, flash back your stock recovery. As long as you are running stock the ota will attempt to download. Even when running non-stock recovery - what will happen is the ota will download and when you accept the update the phone will reboot into your custom recovery and the update won't be applied because the ota relies on the stock recovery being there.
So anyway, you can root, replace custom recovery back with stock and allow the update. You will most likely loose root once the update is applied, but then as long as there are custom recoveries available for the new android version you can flash back to custom recovery, reroot and you should be set.
I did this for a while, but the downside is that if SuperSU updates (or whichever root method you use) and requires a bin update, you won't be able to apply the root bin update unless you are running the custom recovery.
Hope that makes sense, typing from my phone while on a train.

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What I do is this
Unlock Bootloader via HTC DEV website.
Dl a custom recovery I prefer TWRP Recovery flash that via Fastboot.
Then boot into custom recovery on your phone and create a New backup of the stock rom b4 you install SuperSU for root, name it something like (Stock untouched) .
Then flash superSU update zip in recovery.
Once superuser is working do what you want.
Note: I'd go ahead and find and Dl the stock recovery and keep it on hand for when you ready to go back Stock for the OTA update.
Go back to stock
Boot into custom recovery wipe system /data/cache. Then restore the Stock (untouched) backup you made.
Fastboot flash the stock recovery back.
Then relock Bootloader and now you back to Stock and ready to do the OTA update.
Note : this is what I do, everybody got their own way of doing things
Sent from my HTC One_M8 using Tapatalk

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tommy_riley said:
After you root, flash back your stock recovery. As long as you are running stock the ota will attempt to download. Even when running non-stock recovery - what will happen is the ota will download and when you accept the update the phone will reboot into your custom recovery and the update won't be applied because the ota relies on the stock recovery being there.
So anyway, you can root, replace custom recovery back with stock and allow the update. You will most likely loose root once the update is applied, but then as long as there are custom recoveries available for the new android version you can flash back to custom recovery, reroot and you should be set.
I did this for a while, but the downside is that if SuperSU updates (or whichever root method you use) and requires a bin update, you won't be able to apply the root bin update unless you are running the custom recovery.
Hope that makes sense, typing from my phone while on a train.
Click to expand...
Click to collapse
Ok, thank you for the reply. That clears up a little. I can just flash stock recovery every time I want to update. I was able to find a thread that has all the stock recovery file. I have a quick question. Does any version of stock recovery will work? or you want the one that match your current stock recovery. Also, what is Non-WWE-Recoveries?
Here is the thread with all the stock recoveries:
http://forum.xda-developers.com/showthread.php?t=2701376
Let me know. Thank you

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scoot0073 said:
What I do is this
Unlock Bootloader via HTC DEV website.
Dl a custom recovery I prefer TWRP Recovery flash that via Fastboot.
Then boot into custom recovery on your phone and create a New backup of the stock rom b4 you install SuperSU for root, name it something like (Stock untouched) .
Then flash superSU update zip in recovery.
Once superuser is working do what you want.
Note: I'd go ahead and find and Dl the stock recovery and keep it on hand for when you ready to go back Stock for the OTA update.
Go back to stock
Boot into custom recovery wipe system /data/cache. Then restore the Stock (untouched) backup you made.
Fastboot flash the stock recovery back.
Then relock Bootloader and now you back to Stock and ready to do the OTA update.
Note : this is what I do, everybody got their own way of doing things
Sent from my HTC One_M8 using Tapatalk
Click to expand...
Click to collapse
Hello,
I understand your concept for going back to stock. But, I don't get why I have to relock the bootloader. What I mean is, is that necessary for the OTA to work? I thought you only need the stock recovery for the OTA to work. Also, once you have done OTA update, and you want to root the phone again. The downsize is you have to unlock the bootloader again, which will wipe the phone completely and you will have to restore everything, which wastes times.
I like the idea of just restoring the stock recovery, do the OTA upgrade, then flash custom recovery to gain root again. I don't mind repeating that process for each update. But to relock/unlock the bootloader, having to wipe everything is a hassle. Please clarify. Thank you for your help.

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I don't believe you need to relock boot loader for OTA. You do need locked bootloader for RUU full install, but only if S-ON (s-off you can do RUU w/boot loader locked or unlocked) - but that's not what were talking about here - OTA w/ unlocked boot loader = All good.
I believe WWE recovery refers to Europe versions of the recovery, so if in US go for the non-WWE.
I'd stick with trying to lineup stick recovery versions with version of OS software you have installed - so if you are running stock 4.4.2 or 4.4.3 grab the latest stocl recovery available.

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vi6s said:
Hello,
I understand your concept for going back to stock. But, I don't get why I have to relock the bootloader. What I mean is, is that necessary for the OTA to work? I thought you only need the stock recovery for the OTA to work. Also, once you have done OTA update, and you want to root the phone again. The downsize is you have to unlock the bootloader again, which will wipe the phone completely and you will have to restore everything, which wastes times.
I like the idea of just restoring the stock recovery, do the OTA upgrade, then flash custom recovery to gain root again. I don't mind repeating that process for each update. But to relock/unlock the bootloader, having to wipe everything is a hassle. Please clarify. Thank you for your help.
Click to expand...
Click to collapse
Lol.. Yea if S-On relock Bootloader for RUU.
But no you don't need to relock the Bootloader for OTA updates S-On or s-off Sorry for the confusion I was going back n forth with another user and got you mixed up.
Sent from my HTC One_M8 using Tapatalk

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vi6s said:
Ok, thank you for the reply. That clears up a little. I can just flash stock recovery every time I want to update. I was able to find a thread that has all the stock recovery file. I have a quick question. Does any version of stock recovery will work? or you want the one that match your current stock recovery.
Click to expand...
Click to collapse
You need the stock recovery that correspond to your stock software. AT&T software is x.xx.502, and I don't see any corresponding recoveries in exocet's stock nandroid collection, but 1.12.502 and 1.58.502 stock recoveries are posted here: http://forum.xda-developers.com/att-htc-one-m8/development/att-stock-backups-recoveries-otas-t2855966
Also, while eluded to above, it should be clearly stated, no /system files may be modified, in order for OTA to install. So depending on what you intend to change with root, you will either need to put it back to stock (if you modded any system files), restore the stock ROM with a nandroid you made, or a stock ROM posted on XDA.
Alternately, you can quickly return to stock by RUU. Although you either need to relock the bootloader or have s-off to run the RUU. And RUU will also wipe the phone.
So to sum it up, in order to OTA you need:
/system to be returned to stock (stock ROM)
stock recovery
Unlocked bootloader is OK
Root is okay (you will lose root after the OTA)