I see a lot of threads asking about updating to Lollipop and about returning to stock to receive OTA updates.. from rooted users.
I have created this thread as I have strong feelings about rooted users and OTA's in general, so I wanted to collect my thoughts together in a single thread to hopefully persuade rooted users to avoid OTA updates. Of course, you're free to choose to ignore this.
OTA's are simple for unrooted, noob users. They are minimal effort, quick and require no knowledge. However they have a propensity to go wrong - often resulting in a user having to factory reset to get things working.
OTA's are designed to be small to save on data usage. This is achieved by not supplying the entire ROM, kernel or app, but instead, including patches. These patch files (*.p) will unpack the recovery.img, bootloader.img, boot.img or *.apk and insert the new code into it. This means the OTA expects an exact version to install. You cannot skip an OTA and expect to apply a later one because the code in the patch might not "fit". Also, this is why modified users cannot apply an OTA. There are ways for rooted, stock kernel, no modification users to apply OTA updates but it is not recommended
Please note, rooted users will still receive the OTA notification. You do not need to apply it though. Some Custom ROMS even receive it.
Well if you are modified, you have to first return completely to stock to apply an OTA. This is a relatively long process compared to other options available to you. If you are simply rooted with stock kernel and no modifications, you can simply re-apply root after accepting the OTA, but it's a bit messy and still - it's an OTA that can go wrong. I think part of OTA's appeal is you can do it anywhere - but this is also it's biggest problem. rooted users need resources to be available to them so they can remedy whatever needs remedying after application.
In short, it's just not the best option, Why would anyone ever choose "not the best"?
It all depends what you want to keep going forward.
I don't want root or custom recovery
If you no longer want root, simply return to stock using google's factory images. The factory image package contains all the files needed to return to stock:
It also includes a windows batch file (.bat) and a Linux shell script (.sh) that will automate the above. This will wipe your data.
If you don't want to lose your sdcard data, if you have a custom recovery, you can factory reset, fastboot flash individually the recovery.img, system.img and boot.img as this will keep /data partition in tact, which is where your /sdcard is located
I want to keep root
You have a couple options here.
You could like above, fastboot flash individually the system.img and boot.img (not recovery.img) then reflash supersu from your custom recovery. Please note, with lollipop as of now, you need as special modified boot.img, not the stock one - so this still is not the quickest method.
Alternatively, you can flash a pre-rooted zip*. Within a couple of hours of the factory image becoming available, guys from XDA will release pre-rooted zips that you simply flash from a custom recovery. This will be a quick process. Put the zip on your /sdcard, boot into recovery and flash it.
With both these options, you very well may need to factory reset after flashing roms, especially if it's a version jump - just as you may need to do with an OTA update. The benefit of being rooted however, is that you can use titanium backup to backup your apps and take a Nandroid backup too, rooted users upgrading should keep these available on the sdcard before updating.
*Please note with Android 5.0 Lollipop, you need to flash a ROM.zip, Permissive kernel and SuperSU all at once. You have to download all 3 files and flash them one after the other in that order. You can flash some custom kernels, such as elementalx straight over permissive kernel. Also, you can ONLY flash elementalX as it allows root to run at boot (without permissive kernel) however, some apps NEED permissive to run anyway
OTA is designed for noobs. Granted, those root users asking how to return to stock or thinking OTA is the only update method available - are also noobs... If you're going to be rooted, you should understand what you have and what it means to be rooted. Familiarise yourselves with fastboot. Familiarise yourself with your recovery. Learn how to take backups and you will get much more out of your phone that constantly wasting time returning to stock, applying OTA's then re-rooting. You're wasting time doing this - it's a fools errand. I hope this thread helps to open your eyes and your minds.
If you still want to (return to stock in order to) accept OTA updates, even after reading this thread (perhaps because doing things properly mean more work for you) then perhaps you shouldn't be rooted. Having, maintaining and understanding root takes effort and if you're not willing to put the time in, you will become a danger to your phone and possibly a drain on this forum too We write lots of guides and info threads for your benefit. If you have questions, please just ask.
adb and fastboot. What is it? How can it help you? - basic information about adb and fastboot (by @rootSU)
All you need to know about Android | Read this before you post/root ! - Understand the basics before you root (by @abaaaabbbb63 )
How to flash a factory image | Return to stock | Unroot/SAVE your Nexus 5 - Understand how to undo whatever you do before you root (by @abaaaabbbb63 )
OTA Help-Desk - Understand how OTA's work and what this means if you are rooted (by @Sandman-007)