We used to flash Xavier AGX with Nvidia SDK manager, but we found that SDK manager cannot install Jetpack 4.5.1 (with Jetson OS 32.5) on Xavier properly.
BTW, we can install whole Jetpack 4.4 successfully. We’ve also tried to install Jetson OS 32.4 (in Jetpack 4.4) with other Jetson SDK Components in Jetpack 4.5.1 and it seems that everything can be installed properly.