This application can install (and uninstall) the testkit firmware and testkit spoofer plugin, which will completely enable Debug Settings from the settings apps, and everything else you can possibly do on an actual testkit PS Vita. (such as Checker, Quick Sign Up, Installing debug packages in PKG installer, and even multiple PSN accounts.)
The installer makes modifications to vs0, and to the boot_config.txt, so don't power off your Vita or exit the app while installation is ongoing!
Finally, please be aware that this installer will not install on a PSTV, as there appears to be some compatibility issues with numerous things (testkit FW was never designed for PSTV)
Q: Can I get an unrecoverable brick from this?
A: No. If your boot config corrupts (which it 99.9% should not do) then just reboot into safe mode, reinstall the 3.60 retail firmware, and reinstall HENkaku Enso. Moreover, it was proven that you could still access safe mode to reinstall firmware after deleting all of vs0.
Q: I get C2-12828-1 when trying to install/uninstall! Halp!
A: Make sure unsafe homebrew is on or try and untick/retick the box and it should work again.
Testkit Installer Deluxe app - Voxel9
Full testkit spoof trick - SKGleba
kDump.skprx (spoofer plugin) - Zecoxao
(in accordance with memdump license: I made changes to the plugin so it does not log or dump any files)
Activation spoofing - PSVitaDevTestKit95
Support and pointers - CelesteBlue and Modz2014
HENkaku Enso - Team Molecule