Day late and a dollar short...
Daxter does not work with the 'x' folder provided by the Genesis team...
Untold Legends 2 does work but there are a couple of 'freeze' points (or more)...one can be bypassed...the other on Level 4 cannot...
As far as testing UMD games, instead of paying $40, go check out Blockbuster if you live in the U.S....Gamepass is $25/month and most Blockbusters carry PSP games...
Also, Xtreme 2.6 is a copy of Genesis which is a copy of RunUMD with a manually created 'x' folder as explained previously...
However, Xtreme uses an english 'x' folder...therefore, the load/save menus appear on english based PSPs...
You can also patch RunUMD, Genesis or Xtreme so that warning message does not display (no...none of the three programs will brick your PSP...or at least they're not any more likely to brick your PSP than any other piece of homebrew) or the choice to create/dump a new 'x' folder (never, ever do this with Genesis or Xtreme or you've ruined all the work those two teams did)...you just click on the icon and it launches the UMD in your PSP...in the case of Daxter, you just get a black screen and have to pull the battery out of the PSP...
I love these programs...many thanks to everyone involved...and here's hoping some more manual tweaks are on the way to get all 2.6 games working...