The XBR Team has released version as expected XBReboot for Jasper 256/512 MB.
As a reminder, XBReboot allows the image Freebooter 0.02 (which he recovered many functions), to reboot on a kernel patched for the 8955 opportunity unlike XBReboot that takes place directly on the NAND your console. The 8955 kernel patched avoid burning a EFUS (it uses a virtual EFUS) and does not require removing the famous R6T3.
You can then run unsigned code on Xbox 360, use any hard drive, launch games from a USB hard drive or homebrew.
Unfortunately, at present we have no precise information on the implementation of the 256/512 version. We will not fail to inform you of any procedure that is different from our tutorial.