OTA update on rooted 6P using FlashFire

[Twelve Kanaw]

I would like advice to clarify a couple of things before I attempt an OTA update using Flashfire.

The setup: rooted Nexus 6P, Android 7.1.1 build NMF26F, TWRP recovery, SuperSU installed, bootloader unlocked. (Xposed framework is still not available for Nougat, so I haven't monkeyed around with anything like that.)

I've installed FlashFire and read through the manual on the website. There may be some caveats in effect here.

In the section called "Flash ZIP or OTA" several types of OTA are described. With some of them (including Block-based incremental OTA, which is most likely what Android already downloaded and notified me about, though I'm not certain of this - but maybe this is too far into the weeds) we're told that "Generally this type of OTA requires the /system, /vendor and /oem partitions to be completely unmodified stock - bit-by-bit exact copies. Even remounting these partitions in writable mode once may make this type of OTA unflashable. The original modem/radio images may also be required. Stock boot image is usually required, stock recovery image is occasionally required." Some workarounds involving flashing either a RAW backup to the relevant partition or else using stock firmware to flash the same before flashing the OTA are then discussed.

Now for the stupid questions. Because my phone is rooted, is the system partition therefore "modified"? What about uninstalling system apps using Titanium Backup and then reinstalling some of them so as to move them off the system partition? Is this "modifying" the system partition? If I flash the system partition using stock firmware is this going to put those system apps that I uninstalled or moved back onto the system partition? That is, if it even works. I suppose I'd be glad to move them again, come to that. If the OTA update fails the most likely result is that the phone will reboot with nothing modified. I think this is probably what is going to happen but I haven't tried it yet.

I appreciate any discussion of these matters or a pointer to another forum if the FlashFire aspect means I'm on the wrong one.

Thanks.

 

[redduc900]

Download the complete factory image to flash via FF, and not the OTA image.

https://developers.google.com/android/nexus/images?hl=en

Trying to flash the OTA via FF will fail. Leave all the defaults selected in the "Flash ZIP or OTA" section, except for unchecking "Recovery" if you want to retain TWRP. The Userdata partition should be unchecked by default to keep from wiping internal storage. Also verify that SuperSU is injected so you retain root.

 

[Twelve Kanaw]

Thanks redduc900. I was considering doing this if flashing the OTA failed. It's good to get my suspicion confirmed before I try it. A lot of discussion threads, and even the FF website, assume just a bit more understanding than I've got. So I often do things that I'm only mostly confident are correct, at least until they work once. Mostly is not comfortable.

If I've got this right, I can use FF with the factory stock image instead of the (more complicated) procedure described at the Google image download site and then, I suppose, restore Titanium backed up apps and, I reckon, something like an ID backup done with FF beforehand.

It all leads me to reconsider whether the advantages of rooting the 6P are worth the trouble. Back when I had a T-Mobile Galaxy Note II running KitKat 4.4 with a ton of their crapware on it - definitely, yes. Now it's only probably yes but maybe not. I'll think on it a bit and then do the update.

Thanks for the reply.

 

[redduc900]

If you follow the directions on the image download site, your phone will be completely wiped. After running the flash-all.bat script mentioned, your phone will return to an out of the box state (stock recovery, no root, and a wiped userdata partition). If you want to retain root and TWRP while installing the latest monthly security update, then using FF is the only method. If you weren't rooted w/ a custom recovery installed, then you could sideload the latest OTA image via adb.

 

[Twelve Kanaw]

Once again, many thanks.

I want to do this both ways but first the FF way. I dislike pestering people with newby sounding stuff but I dislike more the feeling that I'm only mostly sure that I'm not going to brick my phone. From what I think I understand, the ID backup will probably not be necessary but can't hurt. The Titanium backups will put all my apps + data back. And FF will backup + restore TWRP and put SuperSU back in business after the flash. I'll fire it up in a day or three when I've got some free time.

I'm wondering whether to keep TWRP recovery or not considering all I do with it is back the main partitions up in case I screw up badly. Looks to me like FF has this covered, too.

 

[redduc900]

If you use FF to install the monthly updates, you won't need to use TiBu to restore your apps and data, since the userdata partition is untouched during the flash. Keeping TWRP installed is advantageous in that it can create nandroid backups of your current setup that can be restored via TWRPs Restore option. The stock recovery doesn't offer those options. If you run the flash-all.bat script, it will completely wipe your phone, and your TiBu backup (unless previously sync'd to Google Drive for example) will be lost.

 

[Twelve Kanaw]

All good basic info. I'm sure someone else will read it, too, and not have to ask.

I've read that, of all the ways to update the bootloader, FF can be more dangerous than others such as ADB because the bootloader image is not verified in the process with FF. As one person put it, you could be writing a jpg of your dog for all FF knows or cares. If you're using the factory image from Google, I assume, the danger is remote.

This raises a couple of questions. Is what I said, that the danger is remote with a factory image? Is there any reason to update the bootloader just because you can? I suppose that whatever FF offers to flash by default is going to be OK. When you say bootloader, though, I think you're talking about more than one thing. Primary. Secondary. Maybe a backup. Some stuff in the "trusted zone". It gets complicated.

I expect there's no reason to update the bootloader with these incremental updates. I also expect if you use a factory image you're unlikely to screw up. Got any thoughts?

 

[redduc900]

The newest bootloader is contained in both the full factory image and the OTA update. Whether you sideload the OTA or flash the full image, the bootloader will be updated to the latest version. When using FF to flash an image, the only thing that doesn't get updated is the radio/baseband. In order to flash the newest radio, it will need to be extracted from the factory image and flashed via fastboot (fastboot flash radio radio.img). The safest thing to do is verify the MD5 checksum of the image prior to flashing it. The MD5s for all available images can be found on Google's download sites.

 

[Twelve Kanaw]

Thanks for the info. Some thing I thought I knew are confirmed. Some things are new. All good.