I've looked at 5AJ.1.4 release notes for both SEVM and Panda. Neither one mentions anything about downloading or building x-loader or u-boot:
http://www.omappedia.com/wiki/Panda5AJ.1.4_Release_Notes
There is now something called UsbBoot. Has that replaced x-loader and u-boot, i.e. does it produce an MLO file?