First UMD to require 2.81 Update.
greg from PSP-Hacks.com had this to say:
Although its been reported that many 2.8x titles function fine under Devhook v0.46, this apparently is the first UMD to utilize 2.81-specific modules. "libfont.prx" is the module in question, thus missing fonts if attempted to emulate via Devhook. Nevertheless, here’s a patch from Reborn! Run this PPF [using ppf-o-matic] against LFC’s Star Trek Tactical Assault release.
YAAY! My PSPs back from the dead! Wait.....ZOMBIE!!!
