[Android Q&A, Help & Troubleshooting] Old faithful:
OK, I'm going to chime in since Sparkrite is probably still asleep or busy somewhere else and has been extremely helpful in this thread getting the knowledge out on how to fully take ownership of this tablet. He can't be thanked enough :)

If you want to skip this lengthy intro be my guest, it IS lengthy :silly:

By the way as you probably figured out from my nickname, I've been around probably about as long as you have (presuming from _your_ nickname) and am probably as cautious as you are, as I practically never do anything before fully understanding what I do. I'm the guy who first reads his user manual, then finds the maintenance manual and does the same thing, and even takes his new acquisition apart (when I can) to figure how it works _before_ using it :eek:

I have also read the whole thread and many of its branching linked content, internal and otherwise and feel now, after having spent the last few days after acquiring this tablet a few days ago, that I am ready to go ahead taking the plunge to acquire full ownership of it :).

So here goes, take it with a grain of salt, hopefully it will give a different perspective which will help add to the context you already have to form a clear picture of the process.

My understanding of flashing is that the longer it takes to flash, the more risk there is that something may go wrong. It has something to do with the amount of memory that needs to be flashed (the larger the amount of memory that needs to be perfectly flashed, the greater the risk of experiencing an unrecoverable defect) but also any interference from your PC such as sleep (or other apps and services running in the background) and reliability of the drivers, bugginess or not of the flash tool version you use and, of course, the reliability of your USB connection.

For example, on my phone, I sometimes have to erase the cache partition not once, but a couple of times for it to work properly. Unless I am wrong, it's like any write process. At the physical level, sometimes changing the state of a memory cell does not revert it fully to its new condition of a logical 0 or 1, as it may in fact be rather a .4 or .6 at the physical level, if you understand my meaning.

Steve Gibson wrote a great explanation of this phenomenon as pertaining to magnetic domains on hard disks, and I can tell you from experience, that his utility Spinrite did save my hard drive once that could not be saved before (It took several DAYS to read that defective sector and rewrite that sector to remagnetize it properly, but eventually it worked and save the hard disk - it's been fine ever since, and that hard drive is now 10 years old with no signs of defects anymore)

Bottom line, and that is true for flashing the type of memory we have in SD Cards, flashing more is more risky than flashing less. BUT if you have already successfully reflashed your whole ROM by doing a factory restore, you should feel confident that your internal flash memory is OK and that it *should* work the same way using an external flashing method, at least statistically: doing a factory reset doesn't overwrite the recovery, so the condition of that part of the memory isn't tested when you do a factory reset from the device. It only is when pushing the ROM from the PC using a tool such as SP Flash.

As for failing the recovery flash - I can't say it won't brick the device or otherwise make life miserable for you; the recovery is akin to your old dos autoexec.bat and config.sys getting you into DOS before getting into Windows, in the sense that it operates _below_ the android UI, closer to the hardware layer. And if you were around in the DOS days, getting something wrong there could be a ***** to figure out. In any case, on the physical level the recovery is only a small file that gets flashed rapidly, and as long as the device is in a state that it can communicate with the PC through USB, it should be easy to flash successfully. Just like one could restore Windows functionality by overwriting a single win.ini or system.ini file ;) The only failure mode for this that I could imagine would be a physical disconnect during data transfer, which could presumably result in the usb hardware layer being electrically short-circuited - although I doubt hardware designers would let this be possible.

The worst that can happen in any flashing is that you loose or corrupt parts of the memory that aren't supposed to ever be erased, such as the IMEI (for a phone) or its cellular radio, in this case the NVRAM area which stores such things as the MAC address, in which case it *may* require tools that haven't been leaked out to power users, but I'm not at all sure about that, haven't explored it yet in any great length.

So yes, doing this is not risk-free.

As a matter of fact I had one such brick occurrence with my old HTC Touch, during the first few weeks that I owned it (I was new to flashing), essentially, after trying my first ROM, deciding I was better off with the OEM ROM, after which I lost cellular connectivity. The store where I bought it had a very bright technician (who unfortunately quickly moved up in the company's hierarchy and left the store shortly thereafter), who essentially told me he simply reflashed that part of the memory that was corrupted, even showed me the app, said it was proprietary from the manufacturer, but essentially it was a simple reflash and everything came back OK. Mind you, in those days flashing and smart phones were in their infancy, none of these custom apps were out in the wild at that time and we only had hacked version of other people's tools that were made to work with our phones.

However, today, tools to do that yourself without needing to go though the warranty process are much more readily available and there are many tutorials posted to do so with minimal risk, if you read, read and read to get a good understanding of the actual process. Although new devices such as this tablet aren't as well tested and covered, we have much more to work with and rooting and installing custom recoveries has become both easier and safer than before.

In other words, as long as the device can be read by SP Flash tools, you should be able to restore it. It's like saying as long as your computer can read from its floppy or CD cdrive and your hard drive didn't physically fail, you should be able to revive it. If you fully understand the process, which takes a lot of reading obviously, the risks of hard bricking should be very minimal.

Bottom line, I think you will be fine as long as you keep reading over the next few days to grasp a good understanding of the process and get yourself an external SD card and prepare yourself with all the apps and drivers you will need to make it happen.

Definitely, look at the files in the archive, it's named "recovery.img"

Yes, AFAIK, that is the original Lenovo factory ROM for KitKat (the one for Lollipop has _15-06##_ROW in it, if I remember correctly). That is, assuming this file, for which we only have one source and was uploaded by a poster earlier in this thread, is in fact the same exact factory ROM that Lenovo uses to load this device from the factory.

Just make sure you are using the correct ROM, whether it is for KitKat or Lollipop.

It means after you've set your device up the way you like and built an image using the custom recovery, you'll simply need to restore that (instead of, with the OEM recovery, being forced into the only choice, the OEM unoptimized image). After that you'd simply use that backup app for stuff such as your data and any other app you may have added afterwards.

Right.

It boils down to this: nandroid backup is a full system wide backup of the whole device, everything included, it basically builds an image of your system at the time it is done, everything included. Basically you make one after you're happy with your device and it has become stable. You then use your backup app to restore the small stuff you've added on since your last full system backup

The reason it's important to back everything up onto an _external_ SD card is that should the _internal_ SD card become corrupted (it happen sometimes that you can get a failure message from within the custom recovery, usually caused by a corrupted internal SD card partition), you would need to push the factory ROM onto the tablet again to make it work, wchih essentially wipes _everything_ clean on the internal memory... Needless to say, with all your backups on it, in the words of Jake Blues, you'd essentially be "really up **** Creek"

If you flash a custom recovery from SP Tools and then push SuperSU from the same app and in the custom recovery, load the SuperSU zip, you should be able to acquire root without going through the KingoRoot, which is meant for acquiring (or removing) root access directly from the android UI.

As for restoring the tablet to factory condition, you'd have to do it through SP Flash using the factory ROM and you should then be fresh when you first turned your tablet on.

That's how I'm going to proceed as soon as I get the external SD card in a couple of days.

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Hope this helps and that it wasn't too long and involved... But if you read, read and read, you'll get a full understanding, avoid all pitfalls and truly will become a master of your digital destiny. Like the saying goes, "Measure thrice, cut once" ;)