TN-V is a so called emulated Custom Firmware (eCFW) which features the complete PSP environment (XMB) and can nearly do everything a normal PSP with CFW can do. Inclusive plugin and theme support a lot more!
Adrenaline is different to all previous eCFWs as its the first running outside of the PSP sandbox. Therefore it needs (tai)HENkaku to be enabled to operate! But it also features new options that weren't possible with older eCFWs like using custom grapics filters, taking screenshots, having no filesystem restriction and much more!!
"Adrenaline is a software that modifies the official PSP Emulator using taiHEN CFW framework to make it run a PSP 6.61 custom firmware. Thanks to the power of taiHEN, Adrenaline can inject custom code into the IPL which allows unsigned code to run at boottime."
Note: As Adrenaline needs HENkaku it works on firmware 3.60 only for now!
Official release page (via github.com)
Adrenaline EasyInstaller (via github.com)
Frequently Asked Questions
What are the differences between Adrenaline and TN-V?
Screenshots, custom grapics filter & no filesystem restrictions.
How do I get back to the Vita Live Area?
Hold the home button, select settings and choose exit from there.