The iPad 2 / A5 Bypass (sliverPHP) works by applying generic activation certificates to the device via iDeviceActivation (in reality, this is an iOS 7.x.x bug that Apple patched on every other device but forgot to patch only on the iPad 2). However, due to the properties of the certificates that are applied, they do not persist after a reboot, meaning the bypass is tethered (re-locks after rebooting).
A few years ago, iOS 6.1.3 was signed by Apple. This allowed iPad 2 users to downgrade to iOS 6.1.3, bypass with the iPad 2 server, then update OTA (in the settings application) to iOS 8.4.1. This resulted in an untethered iCloud Bypass, because iOS 8.4.1 is a firmware that supports sideloading 3rd party applications on unactivated devices, so it was super easy to install EtasonJB and delete Setup.app with iFile or Filza. However, Apple is no longer signing iOS 6.1.3, so this method is outdated. If you have an Apple Developer Program Account, you can bypass with the iPad 2 server on 9.3.5 and install the Phoenix jailbreak to delete Setup.app, but this is not a good solution since it is extremely expensive.
Overall, the iPad 2 Bypass Server is a temporary solution. Those wanting a permanent solution should invest in an OEM Arduino Uno and USB Host Shield (when you get any other A5 device in the future, you will be glad you did).
The reason for the black screen issue is when the device has not completed the post-restore progress bar, which resets the filesystem. When Setup.app is deleted and the post-restore progress bar occurs afterwards, the device understands that Setup.app never is and never was a part of the filesystem, so it can ignore it. But if the post-restore progress bar has already completed with Setup.app and then Setup.app is deleted afterwards, the filesystem will think it is missing something and refuse to boot to the home screen. This is why I always tell people to restore and enter DFU mode immediately before attempting any ramdisk method, just to be safe.
On newer MacOS versions, all applications are thoroughly scanned, and Sliver is incorrectly labeled by Apple as incompliant software. The quick fix is to open a Terminal window and type sudo xattr -rd com.apple.quarantine /Applications/Sliver.app/. Another solution is to open Sliver until you get the Move To Trash popup, then 2-finger click on Sliver in your Applications folder, click Get Info, Override Malware Protection. This is usually a small checkbox in the Get Info pane.
There are multiple reasons why this can occur. The most likely and most common issue is that your Arduino Uno is a CLONE. If yours is a blue board that says UNO in big letters, thats an immediate red flag that you bought a fake device. You need an OEM Arduino Uno with the +/- logo and Made In Italy printed on the back (usually OEM boards are green rather than blue). The second most common issue is that 3 essential pins on your usb host shield are not connected to each other. This can easily be fixed by soldering the 3 pins so they make contact. If you google search this topic, you will find plenty of forums on the official arduino website with more details on the exact solution. Lastly, its possible that your LED is connected to the wrong pins, or if you are using an old printer cable, maybe it does not have all the wires attached. I recommend buying brand new LEDS and cables so that wear and tear is never a concern.
Use SYNACKUK checkm8-a5 (NOT a1exdandy), and the latest release of Sliver or SliverM1. Make sure to delete all old versions of Sliver from your Applications folder BEFORE installing the latest version. It is extremely important to only have one copy of Sliver in /Applications! Also, SliverM1 users can access the Arduino Setup Tutorial (included in the app) which explains more details about Arduino-USB patching.
If you are using Sliver 6.2 and still have issues, check out the guides on reddit.com/r/setupapp for ramdisk troubleshooting which have detailed instructions and explanations for every possible problem that could prevent the ramdisk from loading. Or make a new post on the subreddit and describe your issue in detail.
Check to see which files are missing. If the activation_record.plist is missing, or if the FairPlay folder is missing entirely, it means your device was probably iCloud Bypassed by someone else who set a passcode, and it does not have any activation records to back up. If the Activation folder is blank (does not contain any files), then your device is likely USB restricted. Use checkra1nRG to jailbreak. You can also try to reboot or reinstall MacOS. If for some reason these steps still produce a blank activation folder, I recommend trying the FMI OFF method. You can use iRemoval Pro for FMI OFF on your passcode locked/disabled devices (currently unavailable, patched by Apple).
The iPad 2,1 has a bug that makes it unrecognizeable after loading a diagnostics image. Although the exact cause is unknown, it could be a hardware disconnect in the 30-pin DCSD cable. The iRepairBox is now updated and works with the iPad 2,1. Visit AliExpress to purchase the iRepair P10.
Apple patched standard sideloading on bypassed devices for all versions higher than iOS 9, so there is no free method to install H3lix on iOS 10.3.3 / iOS 10.3.4. If you have an Apple Developer Program Account, use Sliver A6 FactoryActivation and install the iPA with Cydia Impactor. Otherwise, you can downgrade to iOS 8.4.1, install H3lix, and update back to iOS 10.3.3 / iOS 10.3.4 to jailbreak, but the downside is the H3lix app will get revoked after 7 days, and you would have to downgrade and upgrade again to re-install it. This method theoretically supports the iPhone 5 and the iPad 4, but it does NOT support the iPhone 5c, since it has no 8.4.1 OTA blobs.
iPhone iCloud Bypass (GSM/MEID Signal Activation) does NOT remove iCloud from Apples servers, only your device. Read my Blog to understand why your iPhone will become locked again if it is restored or updated. Older iPads (WiFi not cellular) can be unlocked forever with purpleSliver. See the iCloud Bypass page for more details.
All Activation Lock Bypass methods require the checkm8 bootrom exploit, which was patched by Apple with the release of the A12 processor. This means that all devices higher than the iPhone X are unsupported, and there is no way to bypass Activation Lock on the iPhone XR, XS, XS Max, 11, 12, or higher until a new exploit is found.