Untethered Triple Boot iOS 8.4.1, 6.1.3 and 10.3.3 on iPad 4 (P102AP)

Huge thanks to @nyan_satan for iOS 10.3.3 installation as secondary OS and @JonathanSeals for downgrading back the iPad to iOS 8.

For this video, I implemented an untethered triple boot involving iOS 8.4.1, iOS 6.1.3 and iOS 10.3.3 on my iPad 4 (P102AP).

I wrote a tutorial about how to implement an untethered iOS Multi-Boot here two years ago,
http://www.pmbonneau.com/apple/ios/mu....
It's a testing version, currently only supports iOS 7.1.2 and 6.1.6 on iPhone 4 (N90AP). Currently, I would recommand you @nyan_satan's guide instead since his one is really more complete and mine hasn't been updated since a long time.

This is my daily driver iPad, the one I use everyday. Before, it was running the lastest available iOS as main only. Somewhere in January 2018, something special has been happened in the world of iOS devices. This was the "downgrade party", where Apple signed many old iOS versions for many devices during a few hours. This was the time to grab those SHSH blobs and downgrade back to a desired iOS version, if blobs were available for. I told a friend to grab the blobs for me during the party since I was away, but had the ECID somewhere on my phone. He sent me the downloaded blobs. I then decided to restore my iPad 4th back to iOS 6.1.3 which I had blobs for. Unfortunately, I noticed that the SHSH blobs had the right ECID, but there were for iPad2,4 (WiFi only) model and I had the iPad2,5 (Wi-Fi + Cellular). I forgot to specify the exact model to my friend, was my mistake. Remembered that iOS 8.4.1 OTA was still signed for iPad 4 and there was an untethered jailbreak for (ETAson JB), so I decided to re-engineer my setup in order to have iOS 8.4.1 as main OS. Implemented this multi-boot during somewhat like four months, because I ran into many issues with secondary OS instances. Now, the setup is complete and I can enjoy my multi-boot iPad. Currently, it is pretty stable. All secondary OS instances use the no-effaceable-storage patch for the DeviceTree, means that I can change iOS passcode without having fear about bootloops. Concept is simple, only iOS 8.4.1 is jailbroken and both secondary OS instances almost have all stock security features turned to on.