dicen en un foro q asi se soluciona temporalmente,pero yo no me aclaro q es lo q hay q hacer aunq entiendo ingles,a ver si alguno q seais mas duchos en temas dashlaunch etc arrojais algo de luz:
FOR RGH / JTAG USERS :
You don't need to uninstall dashlaunch but you can't play without this trick,
If you don't have it, transfer dashlaunch's installer somewhere you can launch it on your xbox and then launch it.
Press RB 2 times.
Click on the option where it says to Unload Dashlaunch From Memory, click to unload.
In the first option in the same menu you go find the game's default.xex and launch it.
Your game doesn't freeze anymore !
And since you just unloaded dashlaunch from memory instead of uninstalling it completely, next time you boot the console it will load dashlaunch normally. (which also means that you'll have to do this trick every time you want to play the game).
While waiting for a dashlaunch fix...