from U3-Robot:

First, I think about making Fix Flasher 1.0 with many fixes, but I made an own firmware called 5.50 U3R.

Changes from 5.50 GEN:
VSH Menu has SHUTDOWN DEVICE option.
Recovery Menu has SPEEDUP MS options.
PSX games may work, but I'm not 100% sure (this means NOT TESTED).

Installation:
1) You must install first 5.50 GEN as a shell (framework).
2) Copy u3rloader folder from a zip file to /PSP/GAME
3) Start 5.50U3R Installer from Game - Memory stick.
4) Click X to install firmware.
5) Enjoy!