WHen you plug in the iPad it will go to the white screen with the apple on it before it reboots in a loop, as soon as you see the white screen with the apple pop up, IMMEDIATELY hold down the power button & home button to do a hard reboot. Once the hard boot starts, the screen goes black, at that point, LET GO of the home & power button. Within seconds, the white screen with the apple will pop up again, again, hold down the power & home screen buttons to do a hard reboot, when the screen goes to black, let go, white screen pops up again with the apple, hold the power button & home button to reboot again, let go once the black screen comes up. When the white screen with the apple logo comes up, repeat the process again. Hold down the power & home buttons, let it go once the black screen pops up & hard reboot again when the white screen comes up. Do it about 5-10 times. The main thing, is catching the iPad while on the white screen with the apple logo before it reboots on its own & repeating that process several times.
YOu do not need to hold down the power button for 10 minutes. Just hard reboot the iPad yourself, anywhere from 5-30 times. Yes, it's time consuming, it will take your full attention, but it's easier & cheaper than buying a new iPad. If your confused as to the hard reboot, especially when it's caught in a loop, just follow the instructions above. Or this:
1) plug in the iPad.
2) when the white screen w/ the apple logo appears, hold down the home & power buttons immediately, let them go when the screen goes to black.
3) after the screen goes black, it will within 2-3 seconds start to reboot itself again & the white screen w/ apple logo comes up. hold down the home & power buttons again, until the screen goes black. Let go. Once the white screen & logo appear, you'll do the same procedure all over again anywhere from 10-30 times. Exactly the same thing, over & over again, a hard reboot once the start up screen appears, then holding down the home & power buttons, forcing a reboot, then letting go when the screen goes dark & immediately doing a hard reboot when the white start up screen w/ the apple logo pops up again.
(**It only takes seconds from start up to reboot to start up again, so pay attention.**)
4) you'll repeat the process above many times. After about the 8-9th time, let the ipad start up & see how much battery life you have. Odds are it will be around 1%. As soon as it boots up & you see that you have 1-2% or so battery life, immediately hold down the power button, JUST the POWER BUTTON. Don't unlock your device, either with Touch ID or your passcode. Just hold down the power button. When the bar comes up across the top of the screen that says, "swipe to power off", swipe that & power down your device.
5) After that, leaving your device OFF & plugged in for a few hours is ideal, but after 20-30 minutes it's usually safe for you to turn your iPad on while it's plugged in & leave it charging. Usually, you have 12-15% at that point. Just leave it plugged in until 100%. I've noticed this glitch tends to occur more frequently if after you've gone through all the steps & finally gotten your device to charge, rather than letting your device charge to 100% you take it off before its done & use it. Doing so increases the frequency with which your device gets caught in the constant reboot cycle, causing it to occur several times a month as opposed every few months if it ever dies while you're using it.
Hope this helps!