[Nexus 7 Q&A, Help & Troubleshooting] GedBlake:
Hi, jeep447...

You're quite welcome to 'pick my brain', as you put it... but don't be too surprised if all you find in there is an oily rag, a half eaten sandwich and a dead D cell battery:).

I'm by no means an Android expert; there are far more knowledgeable posters here on XDA... and they appear to be in possession of secret arcane Android knowledge, that is beyond my understanding:).

However, I will try to help insofar as my knowledge allows. On to your question(s)...

First things first... if you're currently running Jellybean 4.1.2 on the device, then I think it would be a good idea to bring it up to date to KitKat 4.4.2 first... before you start flashing Custom ROMs.

Theoretically, it shouldn't make any difference if you where to flash a Custom ROM now, without bringing it up to date. But there might be an issue with the bootloader...

...which Custom ROMs WILL NOT update.

The bootloader can only (as far as I know) be updated by either...

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a) Allowing an Android update via the normal update route (or manually flashing the OTA yourself in recovery).

...or...

b) Fastboot flashing the full factory image that contains the new bootloader.

-- (however, see my

Addendum

toward the end of this post).

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I am not aware of any Custom ROMs that go anywhere near the bootloader partition. Which is probably a good thing actually, since a bad or incorrect bootloader flash has the potential for HARDBRICKING the Nexus 7.

My recollection is a little hazy... but I think with Jellybean 4.1.2, the bootloader was at version v4.13... since then, there have been two bootloader updates, v4.18, and the current version, which stands at v4.23.

You can check which bootloader you're currently on by booting into the bootloader as follows... shutdown the Nexus 7 completely. Press and hold the VOL DOWN button, whilst holding, press the POWER ON button. The Nexus 7 should now boot into the bootloader. On the lower left hand side of the screen, in a tiny font, you should find (amongst other things), the bootloader version number.

Now all of this detail about bootloaders might not matter... you could happily flash some new Custom ROM... and it might work without any problems with an old bootloader... but, on the hand, it might not:(.

So, I think, before you try tinkering around in the Custom ROM area... and If I where you, I would bring the Nexus 7 completely up to date, running Android 4.4.2 build KOTH49H (and the latest bootloader... v4.23).

The easiest and arguably the safest way of doing this, is to just allow the OTA updates normally, as and when they appear in the notification bar. Or, alternatively go to SETTINGS>>SYSTEM UPDATES > > and tap the CHECK NOW button. This is the method by which 99.9% of all Android users get their updates...

...and which is how I initially updated mine...in November of last year, when I first got my Nexus 7.

Running Jellybean 4.1, straight out of the box, once I connected it to mains power (updates won't occur if your battery is below a certain percentage), and acquired a WiFi signal... my Nexus 7 went through 3 or 4 reboots, upgrading from Jellybean 4.1 to Jellybean 4.1.1 to Jellybean 4.1.2 to Jellybean 4.2 (which introduced the world to Googles new and improved 11 month calender!:)). In December, Jellybean 4.2.1 was released, in time for Santa to arrive, which restored the missing month, December, in the date-picker:).

Your succession of updates will be noticeably longer, as since then, we've had Jellybean 4.2.2, Jellybean 4.3, KitKat 4.4, and finally KitKat 4.4.2.

Along the way, with these updates, your bootloader will also be updated, silently and without you being notified of the fact. Most Nexus 7 owners are probably not even aware of the bootloader, much less if the latest OTA has updated theirs. So, the bootloader is not something you would need to normally flash directly yourself.

Of course there's nothing to stop you applying the OTA updates manually yourself, as I've written about

here

.

However you 'take' the updates, OTA's won't cause you to loose data... all your apps will still be there, as will your pics, videos and music files.

One last point concerning OTA updates... whether applied normally, or flashed manually... you will loose your Custom Recovery (in your case CWM)... and if you're rooted, you'll loose that as well:(... but it's easy enough to get both back after the update.

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Once your Nexus 7 is completely up to date, running KitKat 4.4.2, and before you do anything else, I recommend you make a Nandroid backup. I find it vaguely astonishing that so many people seem to miss this (IMHO) critical step.

Once you have a Nandroid backup under your belt... you can pretty much flash any Custom ROM or Kernel, safe in the knowledge that should anything go wrong with the flash, you can restore back to the point you where at before you flashed that ROM/Kernel or other 'mod'.

In fact, I don't think it would be a bad idea for you to create one now... whilst still running Jellybean 4.1.2... using your recently installed version of CWM.

Nandroid backups, whether created with CWM or TWRP, are a bit like 'restore points' in Windows... and I just think it's good practice and common sense, to have at least one good Nandroid backup stored on the device... before you start flashing stuff.

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Right... I think that covers most of your questions.

I'll try to keep an eye on this thread... in case you have any followup questions.

But I'm going to be pretty busy over the next week or so, what with Christmas on the horizon... so I may not respond immediately.

Good luck with your new Nexus 7... and, as ever... I hope this helps.

**********

Addendum

I've spoken at length about bootloaders and OTA updates. And I think this is your best and least risky way of bringing your Nexus 7 up to date.

Whist there is now available a full factory image for KitKat 4.4.2 build KOTH49 (see my sig for download links), I would avoid it at this time.

Apart from the fact it will completely wipe you're Nexus 7 (which is normal and to be expected) ... the STOCK FACTORY IMAGES, and the bootloaders that ship with them are currently in a bit of a mess. .. and may cause HARDBRICK:(.

See this thread for further details on this...

[WARNING][URGENT] N7 grouper (2012 WiFi) bootloader .img files from Google

.

There are ways of working around this; (you need the bootloader from Build JWR66V)...

...but I suggest you stick with OTA's for now, to bring your device up to date...

Or at least until either Google sort out the 'dogs breakfast/pigs ear' they've made of the factory images... or until you've acquired sufficient knowledge and confidence in modifying a FACTORY STOCK image, such that it fastboot flashes a known GOOD BOOTLOADER.

Rgrds,

Ged.""